DTC P0087 or P0088 - LBS
Diagnostic Instructions
DTC Descriptors
DTC P0087 51: Fuel Rail Low Pressure
Malfunction
DTC P0087 53: Fuel Rail Low Pressure
Malfunction
DTC P0087 55: Fuel Rail Low Pressure Too
Few Transitions
DTC P0088 51: Fuel Rail High Pressure
Malfunction
DTC P0088 52: Fuel Rail High Pressure
Malfunction
DTC P0088 53: Fuel Rail High Pressure
Malfunction
DTC P0088 54: Fuel Rail High Pressure
Malfunction
DTC P0088 57: Fuel Rail High Pressure
Malfunction
DTC P0088 58: Fuel Rail High Pressure
Performance
DTC P0088 59: Fuel Rail High Pressure
Protection Time-Out
DTC P0088 5A: Fuel Rail High Pressure Not
Plausible
DTC P0088 5D: Fuel Rail High Pressure
Malfunction
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 is used to control the fuel pressure at
the fuel rail. The Fuel Pressure Regulator Solenoid 1 is pulse
width modulated (PWM). The ECM supplies the voltage directly to the
Fuel Pressure Regulator Solenoid 1. The ECM controls the
solenoid by grounding the control circuit with a solid state device
called a driver.
Conditions for Running the DTC
| • |
The DTCs runs continuously once the above
conditions are met. |
Conditions for Setting the DTC
P0087 51, P0087 53 and P0087 55
The ECM detects that the rail pressure is below the minimum
threshold.
P0088 51, P0088 52, P0088 58, P0088 59,
P0088 5A and P0088 5D
The ECM detects that the rail pressure exceeds the maximum
positive deviation of rail pressure.
P0088 53
The ECM detects that the rail pressure exceeds the minimum rail
pressure.
P0088 54, P0088 57
The ECM detects that the rail pressure exceeds the maximum rail
pressure.
Action Taken When the DTC Sets
DTCs P0087 51, P0087 53, P0087 55,
P0088 51, P0088 52, P0088 58, P0088 59,
P0088 5A, P0088 5D, P0088 53, P0088 54, and
P0088 57 are Type A DTCs.
Conditions for Clearing the DTC
DTCs P0087 51, P0087 53, P0087 55,
P0088 51, P0088 52, P0088 58, P0088 59,
P0088 5A, P0088 5D, P0088 53, P0088 54, and
P0088 57 are Type A DTCs.
Diagnostic Aids
| • |
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. |
| • |
High Resistance in either circuit of the Fuel
Pressure Regulator 1 will cause a DTC to set. |
| • |
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. |
| • |
If the fuel system pressure is actually too high,
a fuel knock and smoke condition will exist. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
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
- Ignition ON, observe the DTC information with a scan
tool. Verify that no other DTCs are set.
- Engine running, observe the scan tool DTC information
parameter. DTCs P0087, or P0088 should not set.
- 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.
Circuit/System Testing
- Ignition ON, command the fuel pump ON and OFF with a
scan tool. Verify the fuel pump turns ON.
- Ignition OFF, install the EN 34730-1A
fuel pressure gauge .
- Ignition ON, verify the fuel pressure is between
414-550 kPa (60-80 PSI).
- Ignition OFF, disconnect the harness connector at the
Q18A Fuel Pressure Regulator 1.
- Ignition ON, verify a test lamp illuminates between
the ignition voltage circuit terminal 1 and ground.
| ⇒ |
If the test lamp does not illuminate, repair the
ignition voltage circuit for a short to ground or an open/high
resistance. |
- Ignition ON, test for 3-4 V between the control
circuit terminal 2 and ground.
| ⇒ |
If less than the specified range, test the control
circuit for an open or a short to ground. If the circuit tests
normal, replace the K20 Engine Control Module. |
| ⇒ |
If greater than the specified range, test the
control circuit for a short to voltage. If the circuit tests
normal, replace the K20 Engine Control Module. |
- Inspect and repair one of the following
conditions:
Low Pressure
| • |
Injection nozzle stuck in open position |
| • |
Leakage in the fuel rail pressure regulator |
| • |
Worn fuel injection pump |
High Pressure
| • |
Fuel injection pump stuck open |
| • |
Fuel rail pressure regulator stuck closed |
| • |
Restricted fuel injector |
- If all circuit tests normal, replace the
Q18A Fuel Pressure Regulator 1.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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