DTC P0087 or P0088 (LBY)
| DTC P0087 or P0088 (LBY) |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC P0087 51
Fuel Rail Low Pressure
DTC P0087 53
Fuel Rail Low Pressure
DTC P0087 54
Fuel Rail Low Pressure
DTC P0087 55
Fuel Rail Low Pressure
DTC P0087 5C
Fuel Rail Low Pressure
DTC P0087 5D
Fuel Rail Low Pressure
DTC P0087 5E
Fuel Rail Low Pressure
DTC P0087 5F
Fuel Rail Low Pressure
DTC P0087 60
Fuel Rail Low Pressure
DTC P0087 61
Fuel Rail Low Pressure
DTC P0087 62
Fuel Rail Low Pressure
DTC P0087 64
Fuel Rail Low Pressure
DTC P0087 65
Fuel Rail Low Pressure
DTC P0087 66
Fuel Rail Low Pressure
DTC P0088 51
Fuel Rail High Pressure
DTC P0088 52
Fuel Rail High Pressure
DTC P0088 53
Fuel Rail High Pressure
DTC P0088 54
Fuel Rail High Pressure
DTC P0088 57
Fuel Rail High Pressure
DTC P0088 58
Fuel Rail High Pressure
DTC P0088 59
Fuel Rail High Pressure
DTC P0088 5A
Fuel Rail High Pressure
DTC P0088 5B
Fuel Rail High Pressure
DTC P0088 5C
Fuel Rail High Pressure
DTC P0088 5D
Fuel Rail High Pressure
DTC P0088 5E
Fuel Rail High Pressure
DTC P0088 5F
Fuel Rail High Pressure
DTC P0088 60
Fuel Rail High Pressure
DTC P0088 61
Fuel Rail High Pressure
DTC P0088 62
Fuel Rail High Pressure
DTC P0088 63
Fuel Rail High Pressure
DTC P0088 64
Fuel Rail High Pressure
DTC P0088 65
Fuel Rail High Pressure
DTC P0088 66
Fuel Rail High Pressure
DTC P0088 67
Fuel Rail High Pressure
| Circuit/System Description |
The engine control module (ECM) uses commanded fuel pump flow to determine a desired fuel rail pressure. The ECM monitors fuel rail pressure with the fuel rail pressure sensor. The Fuel Pressure Regulator Solenoid 1 and Fuel Pressure Regulator Solenoid 2 are used to control the fuel pressure at the fuel rail. The Fuel Pressure Regulator Solenoid 1 and Fuel Pressure Regulator Solenoid 2 are pulse width modulated (PWM). The ECM supplies the voltage directly to the Fuel Pressure Regulator Solenoid 1 and Fuel Pressure Regulator Solenoid 2. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver.
| Conditions for Running the DTC |
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The engine is running.
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The DTCs run continuously when the above conditions are met.
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| Conditions for Setting the DTC |
P0087
The ECM detects that the rail pressure is below the minimum threshold.P0088
The ECM detects that the rail pressure exceeds the maximum positive deviation of rail pressure.| Action Taken When the DTC Sets |
DTCs P0087 and P0088 are Type A DTCs.
| Conditions for Clearing the DTC |
DTCs P0087 and P0088 are Type A DTCs.
| Diagnostic Aids |
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A restricted fuel supply line, a leakage in the high pressure section, too much or too little fuel in the low pressure line may cause DTCs to set. When ambient temperatures are below 0°C (32°F), the fuel tank pickup screen may be iced over from water in the fuel tank.
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High Resistance in either circuit of the Fuel Pressure Regulator 1 will cause a DTC to set.
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High Resistance in either circuit of the Fuel Pressure Regulator 2 will cause a DTC to set.
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There are no driveability concerns associated with the fuel rail pressure regulator unless a DTC is present. One of the causes of these DTCs is a sticking fuel rail pressure regulator.
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If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist.
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| Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EN 34730-1A Fuel Pressure Gauge
For equivalent regional tools, refer to Special Tools .
| Circuit/System Verification |
| 1. |
Ignition ON, observe the DTC information with a scan tool. Verify that no other DTCs are set.
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| 2. |
If any other DTCs are set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle
for further diagnosis.
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| 3. |
Engine ON, observe the DTC's information parameter on the scan tool. DTCs P0087 or P0088 should not be set.
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| 4. |
Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
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| Circuit/System Testing |
| 1. |
Ignition ON, command the fuel pump ON and OFF with a scan tool. Verify the fuel pump turns ON.
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| 2. |
If the fuel pump does not turn ON, refer to
Fuel Pump Electrical Circuit Diagnosis
for further diagnosis.
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| 3. |
Ignition OFF, install the fuel pressure gauge
EN-34730-1A
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| 4. |
Ignition ON, verify the fuel pressure is between 414-550 kPa (60-80 PSI).
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| 5. |
If not within the specified range, refer to
Fuel System Diagnosis
for further diagnosis.
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| 6. |
Ignition OFF, disconnect the harness connector at the Q45A Fuel Rail Pressure Regulator 1.
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Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 2 and ground.
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| 8. |
If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance.
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| 9. |
Ignition ON, test for 3-4 V between the control circuit terminal 1 and ground.
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| 10. |
If less than the specified range, test the control circuit for an open or a short to ground. If circuit tests normal, replace the K20 Engine Control Module.
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| 11. |
If greater than the specified range, test the control circuit for a short to voltage. If circuit tests normal, replace the K20 Engine Control Module.
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Ignition OFF, disconnect the harness connector at the Q45B Fuel Rail Pressure Regulator 2.
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| 13. |
Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 2 and ground.
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If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance.
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Ignition ON, test for 3-4 V between the control circuit terminal 1 and ground.
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If less than the specified range, test the control circuit for an open or a short to ground. If circuit tests normal, replace the K20 Engine Control Module.
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| 17. |
If greater than the specified range, test the control circuit for a short to voltage. If circuit tests normal, replace the K20 Engine Control Module.
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| 18. |
Inspect and repair one of the following conditions:
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A fuel system leak
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Restricted fuel filter
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Injection nozzle stuck in open position
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Leakage in the fuel rail pressure regulator
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Worn fuel injection pump
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Restricted fuel return
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Fuel injection pump stuck open
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Fuel rail pressure regulator stuck closed
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Restricted fuel injector
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| 19. |
If all circuit tests normal, replace the Q45A Fuel Rail Pressure Regulator 1 or Q45B Fuel Rail Pressure Regulator 2.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Fuel Injection Pump Replacement
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Fuel Injector Replacement (LBY/A20DTR)
Fuel Injector Replacement (LBS/A20DTH)
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Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
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Control Module References
for ECM replacement, setup, and programming
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