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Discussion Starter #1
What can be done if your car doesn’t start and you need to release fuel pressure?
I’m replacing my fuel pump and need advice
 

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FUEL SYSTEM PRESSURE RELEASE PROCEDURE

WARNING:
The fuel system is under constant pressure even with engine off. Until the fuel pressure has been properly relieved from the system, do not attempt to open the fuel system. Do not smoke or use open flames/sparks when servicing the fuel system. Wear protective clothing and eye protection. Make sure the area in which the vehicle is being serviced is in a well ventilated area.

1.Remove fuel fill cap.

2.Remove lower rear seat cushion (Refer to 23 - Body/Seats/SEAT/Removal)

125449


3.Remove the fuel pump module cover (1).

125450


4.Disconnect electrical connector (4) form fuel pump module.

5.Start and run engine until it stalls.

6.Attempt to restarting engine a few times until the engine will no longer start.

7.Turn ignition key to OFF position.

8.Disconnect and isolate the negative battery cable. If equipped with an Intelligent Battery Sensor (IBS), disconnect the IBS connector first before disconnecting the negative battery cable.

9.Place a shop towel below and disconnect the fuel line quick-connect fittings at the fuel pump module, (Refer to 14 - Fuel System/Fuel Delivery/FITTING, Quick Connect - Standard Procedure) .

NOTE:
After servicing the fuel system, one or more Diagnostic Trouble Codes (DTC's) may have been stored in Powertrain Control Module (PCM) memory due to disconnecting fuel pump module circuit. A diagnostic scan tool must be used to erase a DTC.



14 - Fuel System / Fuel Delivery, Gas / MODULE, Fuel Pump / Removal

REMOVAL

WARNING:
Risk of injury to eyes and skin from contact with fuel. Wear protective clothing and eye protection. Risk of poisoning from inhaling and swallowing fuel. Pour fuel only into appropriately marked and approved containers. Failure to follow these instructions may result in possible serious or fatal injury.

WARNING:
The fuel system is under constant high pressure even with engine OFF. Until the fuel pressure has been properly released from the system, do not attempt to open the fuel system. Do not smoke or use open flames/sparks when servicing the fuel system. Make sure the area in which the vehicle is being serviced is in a well ventilated area. Failure to comply may result in serious or fatal injury.

1.Perform the fuel system pressure release procedure (Refer to 14 - Fuel System/Fuel Delivery - Standard Procedure) .

NOTE:
The fuel pump module has to be properly located in the fuel tank for the fuel level gauge to work properly.

2.Disconnect and isolate the negative battery cable.

3.Remove bolts and the rear seat cushion.

125451


4.Remove bolts (2) and lift up on the fuel pump module access cover and disconnect the wire harness connector (4).

125452


5.Use a marker and place a mark across the position of the fuel pump module lock-ring, fuel pump module and the fuel tank prior to removal.

6.Disconnect the fuel tank vapor line (1, 3) from fuel pump module.

125453


7.Disconnect the fuel lines (2) from the fuel pump module.

NOTE:
Prior to removing the fuel pump module, use compressed air to remove any accumulated dirt and debris from around fuel tank opening.

8.Position the lock-ring remover/installer (2) 9340 into the notches on the outside edge of the lock-ring (3).

125454


9.Install a 1/2 inch drive breaker bar into the lock-ring remover/installer 9340 .

10.Rotate the breaker bar (1) counterclockwise and remove the lock-ring (3).

WARNING:
The fuel pump module reservoir does not empty out when the tank is drained. The fuel in the reservoir will spill out when the module is removed.

NOTE:
Do not spill fuel into the interior of the vehicle.

11.Lift up and removed the fuel pump module out of the fuel tank using caution not spill fuel inside the vehicle or bend the float arm.

12.Tip the fuel pump module on its side and drain all fuel from the reservoir.

13.Remove and discard the rubber O-ring seal.

125455
 

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Discussion Starter #3
I have the Chilton. My question was what can I do if my car won’t start and it can’t run until it stalls? Is there another way to release the pressure?
 

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When you turn the key to ON, do you hear the fuel pump hum? You can have a helper listen by the passenger rear tire. If it hums, it is likely not the pump. Vehicles with a BCM have a complex series of events to start the engine. I just posted a diagnostic a few days ago.
See the thread:

Have you tried swapping the fuel pump relay in the PDC?
 

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Discussion Starter #5
When you turn the key to ON, do you hear the fuel pump hum? You can have a helper listen by the passenger rear tire. If it hums, it is likely not the pump. Vehicles with a BCM have a complex series of events to start the engine. I just posted a diagnostic a few days ago.
See the thread:

Have you tried swapping the fuel pump relay in the PDC?
I just replaced the starter. All fuses working properly. Tried jumping the car but a no go. I do not hear the fuel pump. I already have the rear seats out. I’m concerned with safety. My husband js passed away, I’m living in the middle of the Navajo Reservation for work, and if you want your car fixed: you fix it yourself.
Scanned and got these codes: P104A, P104C, P1048, P1046, and P0456. What does it all mean?
And thanks Alpinegreenneon!:)
 

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Sorry to hear you have the 1.4 engine. According to the codes, this is a PCM problem. The evap code is not causing the no start but the others are. It's not the fuel pump.

28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P104A-00-CYLINDER 3 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)






28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P104C-00-CYLINDER 4 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P1048-00-CYLINDER 2 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P1046-00-CYLINDER 1 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P0456-00-EVAP PURGE SYSTEM SMALL LEAK

Theory of Operation

EVAPORATIVE SYSTEM OVERVIEW: The Powertrain Control Module (PCM) monitors the Evaporative Emission System operation. The primary concern being monitored is the integrity of the system against leaks. The basic strategy used is that in a sealed system, pressure will naturally increase or decrease in relation to temperature. As temperature increases, so does pressure inside the system. And conversely, as temperature decreases, pressure in the system will decrease as well and will eventually turn into a vacuum if no leaks are present. Even the smallest of leaks can be accurately detected in this manner. The ESIM has multiple functions. There are two weighted seals that keep the system normally closed from the atmosphere. The weighted seals are used to maintain the system pressure between +1 inch of water and -2 inches of water. Anytime (engine-on or engine-off) that pressure or vacuum reaches these thresholds, the weights will lift and provide relief. There is also an internal vacuum actuated switch that closes when the vacuum reaches a calibrated value. This is beneficial because the induced vacuum during a subsequent declining temperature will achieve the switch closed (pass threshold) sooner than if the tank had to decay from a higher built up pressure.

ESIM SWITCH STUCK CLOSED MONITOR: At ignition off, the state of the ESIM switch is evaluated. If the switch is open, a pass flag is set and PCM will complete power down. If the switch is closed, the PCM will wait a calibrated delay time and open the OBD Vent Valve. This should vent the vacuum in the Fuel Tank to atmosphere through the Intake Manifold. If the switch opens, a pass flag is set and the PCM will power down. If the PCM detects that the ESIM switch is still closed after a calibrated time, an error is detected and a switch stuck closed failure is set at the next engine run cycle.

SMALL LEAK MONITOR: This is an accumulative monitor and the data from each valid event is recorded and added to the previously recorded events. The PCM timer records the engine on/drive cycle and engine off time for each small leak monitor event. For an event to be valid the PCM must see;

1.An engine on/drive cycle for a minimum of 10 minutes.

NOTE: The engine on timer will stop counting after a maximum of 26 minutes.

2.And, when the engine is shut down, an engine off timer starts. There is a 12 minute delay time in which the PCM will ignore ESIM Switch input. The engine off timer period will continue to count until one of the three conditions exist:
•The engine is started without a switch closure during the event.

NOTE: At the next key on cycle a determination is made as to whether the event was valid and the information is kept.

•An ESIM Switch closed input is received after the 12 minute delay during the event.

NOTE: If the switch closed input is received, the PCM records that the switch has closed, stores the engine shut down time, then goes to sleep.

•After a maximum of 1051 minutes without an ESIM Switch closure during the event.

The accumulative monitor will increment and start over after both timers have reached a calibrated threshold (Engine on - 100 minutes and Engine off - 4200 minutes). When the monitor has exceeded the calibrated accumulated engine on and engine off thresholds, the system is evaluated and the accumulated timer starts over.

LEAK SIZE DETERMINATION: If the PCM did not see an ESIM Switch closed signal during the previous ignition off cycle, and the event was valid, an intrusive leak test is run to determine if a large leak is present on the next cold start.

Immediately after start-up, while the engine is cold, the Purge Solenoid is opened to create a vacuum in the evaporative system to a calibrated vacuum point that is beyond the ESIM Switch closing threshold. The pass/fail time will vary based on the total fuel volume at the time of the test.

•If the switch does not close at all during purging, because of a switch that is stuck open or vacuum cannot be created below 1.0 in Hg within a calibrated time threshold, it is determined to be a general evaporative system failure (P0440).
•If vacuum is created and the switch has closed, the PCM monitors how long it takes for the switch to open. If the switch opens before the maximum calibrated time, it is determined to be a large leak (P0455).
•If vacuum is created and the switch has closed, the PCM monitors how long it takes for the switch to open. If the switch stays closed longer than a maximum calibrated time before opening, it is determined that a large leak is not present and the Small Leak Monitor will continue to run until the accumulative monitor increments. If no ESIM Switch closures were recorded during the entire increment, it is determined that a small leak is present (P0456)

PURGE FLOW MONITOR: The operation of the Purge Solenoid and evaporative purge flow is monitored using inputs from the ESIM Switch and Fuel Tank Pressure Sensor. The Purge Flow Monitor will only run if the Small Leak Monitor recorded a pass on the previous ignition off event and the test data was valid. Because the leak detection diagnostics can only verify that the fuel tank system is sealed while the purge valve is closed, it cannot determine if the purge line between the solenoid and Intake Manifold is pinched or leaking. The Purge Flow Monitor is needed to verify these failure modes. The Purge Flow Monitor works on the premise that as flow through the system increases, so does the pressure drop in the system. The PCM monitors the Fuel Tank Pressure Sensor and looks for increasing vacuum in the Fuel Tank with increasing purge flow. Conversely, it looks for decreasing vacuum in the Fuel Tank with decreasing flow.

•With the engine running and enable conditions met, the non-intrusive purge monitor looks for a calibrated increase in vacuum in the fuel tank with increased purge flow, referred to as phase 1. If phase 1 passes, the purge monitor looks for a calibrated decrease in vacuum in the Fuel Tank with decreasing purge flow, referred to as phase 2. If phase 2 passes, the purge monitor is complete. If the purge flow monitor fails either phase, or does not complete both phases within a specified time, an intrusive test is initiated to verify the results from the non-intrusive test.
•The intrusive diagnostic uses the same two phases to analyze the system. However, the intrusive test actuates the Purge Solenoid such that the differences are much more pronounced allowing a more accurate test result. If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441).

PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the Evaporative emissions system is correctly operating. The Purge flow monitor in boost is enabled to run this trip the exact same way as Purge Flow Monitor.

•The Turbo Purge Monitor will only go intrusive on this trip after a small leak passing event.
•The Monitor will only run when there is a sustained stable boost condition and not when the vehicle is at wide open throttle.
•The Monitor waits a calibrated time while stabilized boost is achieved, it then turns on the OBD Bypass Valve (#19) to relieve vacuum only. It then turns on the purge and the monitor looks for only a phase 1 decrease in vacuum in the fuel tank. If the vacuum cannot be achieved the monitor fails. (P1CEA)


When Monitored and Set Conditions

When Monitored: This diagnostic runs when the following conditions are met:

•After the ignition is off for a calibrated time.
•Fuel level less than 88%.
•Ambient temperature between 4°C and 43°C (39°F and 109°F).
•Elevation is below 8000 feet.


Set Conditions:

•If no ESIM Switch closures were recorded during an entire accumulative increment, it is determined that a small leak is present.


Default Actions:

•The MIL light will illuminate.


Possible Causes

ESIM INTERNAL CHECK VALVES LEAKING
PURGE SOLENOID LEAKING
SMALL EVAP SYSTEM LEAK
 

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Registered
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21 Posts
Discussion Starter #7
Ok so wh
Sorry to hear you have the 1.4 engine. According to the codes, this is a PCM problem. The evap code is not causing the no start but the others are. It's not the fuel pump.

28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P104A-00-CYLINDER 3 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)






28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P104C-00-CYLINDER 4 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P1048-00-CYLINDER 2 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P1046-00-CYLINDER 1 OIL SUPPLY SOLENOID VALVE OVERCURRENT

Theory of Operation

Multi-Air is an electronically controlled variable intake valve phase and lift system. Unlike conventional intake valve phase and lift system which controls all the cylinder intake valves simultaneously and in the same proportion; Multi-Air, through the use of an electronically controlled “ hydraulic link” between the camshaft and intake valve, allowing for each intake valve to be controlled independently. The valve lift and timing can be adjusted infinitely.

The Multi-Air valve train has a mechanical camshaft lobe acting on a hydraulic pump located between the camshaft intake lobe and the intake valve. The pump provides oil under pressure to a two-way electro-hydraulic solenoid valve called the Variable Valve Actuator (VVA) Solenoid. The VVA Solenoid is electronically controlled during the specific intake cam lobe event by the Powertrain Control Module (PCM). During the event the VVA Solenoid is commanded to either hold oil pressure or bleed oil. The Variable Valve Actuator (VVA) Solenoid is a normally open solenoid. The PCM provides 12 volts to close the solenoid. The position of the VVA Solenoid determines the intake valve timing and lift. This change on valve action is similar to creating a change in the camshaft lobe profile affecting lift and duration of the valve opening.


When Monitored and Set Conditions

When Monitored: This diagnostic runs continuously when the following conditions are met:

•With the engine running.
•With no battery or ASD Relay DTCs active.


Set Conditions:

•This fault is set when the VVA solenoid current feedback level in voltage is out of range.


Default Actions:

•The MIL light will illuminate.


Possible Causes

POWERTRAIN CONTROL MODULE (PCM)



28 - DTC-Based Diagnostics / MODULE, Powertrain Control (PCM) / Diagnosis and Testing

P0456-00-EVAP PURGE SYSTEM SMALL LEAK

Theory of Operation

EVAPORATIVE SYSTEM OVERVIEW: The Powertrain Control Module (PCM) monitors the Evaporative Emission System operation. The primary concern being monitored is the integrity of the system against leaks. The basic strategy used is that in a sealed system, pressure will naturally increase or decrease in relation to temperature. As temperature increases, so does pressure inside the system. And conversely, as temperature decreases, pressure in the system will decrease as well and will eventually turn into a vacuum if no leaks are present. Even the smallest of leaks can be accurately detected in this manner. The ESIM has multiple functions. There are two weighted seals that keep the system normally closed from the atmosphere. The weighted seals are used to maintain the system pressure between +1 inch of water and -2 inches of water. Anytime (engine-on or engine-off) that pressure or vacuum reaches these thresholds, the weights will lift and provide relief. There is also an internal vacuum actuated switch that closes when the vacuum reaches a calibrated value. This is beneficial because the induced vacuum during a subsequent declining temperature will achieve the switch closed (pass threshold) sooner than if the tank had to decay from a higher built up pressure.

ESIM SWITCH STUCK CLOSED MONITOR: At ignition off, the state of the ESIM switch is evaluated. If the switch is open, a pass flag is set and PCM will complete power down. If the switch is closed, the PCM will wait a calibrated delay time and open the OBD Vent Valve. This should vent the vacuum in the Fuel Tank to atmosphere through the Intake Manifold. If the switch opens, a pass flag is set and the PCM will power down. If the PCM detects that the ESIM switch is still closed after a calibrated time, an error is detected and a switch stuck closed failure is set at the next engine run cycle.

SMALL LEAK MONITOR: This is an accumulative monitor and the data from each valid event is recorded and added to the previously recorded events. The PCM timer records the engine on/drive cycle and engine off time for each small leak monitor event. For an event to be valid the PCM must see;

1.An engine on/drive cycle for a minimum of 10 minutes.

NOTE: The engine on timer will stop counting after a maximum of 26 minutes.

2.And, when the engine is shut down, an engine off timer starts. There is a 12 minute delay time in which the PCM will ignore ESIM Switch input. The engine off timer period will continue to count until one of the three conditions exist:
•The engine is started without a switch closure during the event.

NOTE: At the next key on cycle a determination is made as to whether the event was valid and the information is kept.

•An ESIM Switch closed input is received after the 12 minute delay during the event.

NOTE: If the switch closed input is received, the PCM records that the switch has closed, stores the engine shut down time, then goes to sleep.

•After a maximum of 1051 minutes without an ESIM Switch closure during the event.

The accumulative monitor will increment and start over after both timers have reached a calibrated threshold (Engine on - 100 minutes and Engine off - 4200 minutes). When the monitor has exceeded the calibrated accumulated engine on and engine off thresholds, the system is evaluated and the accumulated timer starts over.

LEAK SIZE DETERMINATION: If the PCM did not see an ESIM Switch closed signal during the previous ignition off cycle, and the event was valid, an intrusive leak test is run to determine if a large leak is present on the next cold start.

Immediately after start-up, while the engine is cold, the Purge Solenoid is opened to create a vacuum in the evaporative system to a calibrated vacuum point that is beyond the ESIM Switch closing threshold. The pass/fail time will vary based on the total fuel volume at the time of the test.

•If the switch does not close at all during purging, because of a switch that is stuck open or vacuum cannot be created below 1.0 in Hg within a calibrated time threshold, it is determined to be a general evaporative system failure (P0440).
•If vacuum is created and the switch has closed, the PCM monitors how long it takes for the switch to open. If the switch opens before the maximum calibrated time, it is determined to be a large leak (P0455).
•If vacuum is created and the switch has closed, the PCM monitors how long it takes for the switch to open. If the switch stays closed longer than a maximum calibrated time before opening, it is determined that a large leak is not present and the Small Leak Monitor will continue to run until the accumulative monitor increments. If no ESIM Switch closures were recorded during the entire increment, it is determined that a small leak is present (P0456)

PURGE FLOW MONITOR: The operation of the Purge Solenoid and evaporative purge flow is monitored using inputs from the ESIM Switch and Fuel Tank Pressure Sensor. The Purge Flow Monitor will only run if the Small Leak Monitor recorded a pass on the previous ignition off event and the test data was valid. Because the leak detection diagnostics can only verify that the fuel tank system is sealed while the purge valve is closed, it cannot determine if the purge line between the solenoid and Intake Manifold is pinched or leaking. The Purge Flow Monitor is needed to verify these failure modes. The Purge Flow Monitor works on the premise that as flow through the system increases, so does the pressure drop in the system. The PCM monitors the Fuel Tank Pressure Sensor and looks for increasing vacuum in the Fuel Tank with increasing purge flow. Conversely, it looks for decreasing vacuum in the Fuel Tank with decreasing flow.

•With the engine running and enable conditions met, the non-intrusive purge monitor looks for a calibrated increase in vacuum in the fuel tank with increased purge flow, referred to as phase 1. If phase 1 passes, the purge monitor looks for a calibrated decrease in vacuum in the Fuel Tank with decreasing purge flow, referred to as phase 2. If phase 2 passes, the purge monitor is complete. If the purge flow monitor fails either phase, or does not complete both phases within a specified time, an intrusive test is initiated to verify the results from the non-intrusive test.
•The intrusive diagnostic uses the same two phases to analyze the system. However, the intrusive test actuates the Purge Solenoid such that the differences are much more pronounced allowing a more accurate test result. If the PCM detects a failure during the intrusive test, a purge system performance fault is set (P0441).

PURGE FLOW MONITOR IN BOOST: Turbocharged engines purge while the engine is in boost. This is achieved by having additional purge hoses and Hardware. The Boost purge monitor is used to check that this part of the Evaporative emissions system is correctly operating. The Purge flow monitor in boost is enabled to run this trip the exact same way as Purge Flow Monitor.

•The Turbo Purge Monitor will only go intrusive on this trip after a small leak passing event.
•The Monitor will only run when there is a sustained stable boost condition and not when the vehicle is at wide open throttle.
•The Monitor waits a calibrated time while stabilized boost is achieved, it then turns on the OBD Bypass Valve (#19) to relieve vacuum only. It then turns on the purge and the monitor looks for only a phase 1 decrease in vacuum in the fuel tank. If the vacuum cannot be achieved the monitor fails. (P1CEA)


When Monitored and Set Conditions

When Monitored: This diagnostic runs when the following conditions are met:

•After the ignition is off for a calibrated time.
•Fuel level less than 88%.
•Ambient temperature between 4°C and 43°C (39°F and 109°F).
•Elevation is below 8000 feet.


Set Conditions:

•If no ESIM Switch closures were recorded during an entire accumulative increment, it is determined that a small leak is present.


Default Actions:

•The MIL light will illuminate.


Possible Causes

ESIM INTERNAL CHECK VALVES LEAKING
PURGE SOLENOID LEAKING
SMALL EVAP SYSTEM LEAK
What does that all mean? And how does that happen when I have been taking care of my engine?
Sherri
 

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The 4 MultiAir codes are saying that voltage to the intake valve control are out of range. That is controlled by the PCM. The PCM is the brain that works the MultiAir and that is why you can't start. Electronics can fail without any input from what you did or did not do. Evap problems seem to happen to almost everyone eventually because gasoline vapor destroys rubber hoses and electronic parts like the ESIM and purge control valve. Hopefully, you can find a sympathetic dealer.
 

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Discussion Starter #9
The 4 MultiAir codes are saying that voltage to the intake valve control are out of range. That is controlled by the PCM. The PCM is the brain that works the MultiAir and that is why you can't start. Electronics can fail without any input from what you did or did not do. Evap problems seem to happen to almost everyone eventually because gasoline vapor destroys rubber hoses and electronic parts like the ESIM and purge control valve. Hopefully, you can find a sympathetic dealer.
So is my car done? Can it be repaired? Should I look for another car??
 

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Of course it can be repaired but it is not something you can do yourself. While it's easy to physically R & R a PCM, the problem is getting the electronics to like each other. Something only a dealer can do.
The evap stuff is easy once you figure out what to replace. It may take a smoke machine to diagnose, something a dealer has.
Find a dealer you can trust that won't drain your wallet. Tell them the codes and get an estimate before they start. Payments for another vehicle will likely set you back more than the repair.
 

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Of course it can be repaired but it is not something you can do yourself. While it's easy to physically R & R a PCM, the problem is getting the electronics to like each other. Something only a dealer can do.
The evap stuff is easy once you figure out what to replace. It may take a smoke machine to diagnose, something a dealer has.
Find a dealer you can trust that won't drain your wallet. Tell them the codes and get an estimate before they start. Payments for another vehicle will likely set you back more than the repair.
Hey thank you a bunch. You’ve been very helpful and I’ll follow your advice.
 
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