DTC P0088 - LPL or LPV
Diagnostic Instructions
DTC Descriptors
DTC P0088 52: Fuel Rail High Pressure
DTC P0088 5B: 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 is used to control the fuel pressure. The fuel
pressure regulator solenoid is pulse width modulated (PWM). The ECM
supplies the voltage directly to the fuel pressure regulator
solenoid. 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
The ECM detects that the rail pressure exceeds the maximum
positive deviation of rail pressure.
Action Taken When the DTC Sets
DTC P0088 is a Type C DTC.
Conditions for Clearing the DTC
DTC P0088 is a Type C DTC.
Diagnostic Aids
| • |
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
Description and Operation
Fuel System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
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 OFF, disconnect the harness connector at the
G18 High Pressure Fuel Pump.
- 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. |
- Disconnect the X2 harness connector at the
K20 Engine Control Module.
- Ignition ON, test for less than 0.3 V between the
signal circuit at the harness connector from G18 High Pressure
Fuel Pump terminal 2 and ground.
| ⇒ |
If greater than the specified range, test the
signal circuit for a short to Voltage. If the circuit tests normal,
replace the K20 Engine Control Module. |
- Ignition OFF, test for greater than 500 kΩ
between the signal circuit terminal 2 and ground.
| ⇒ |
If less than the specified range, test the signal
circuit for a short to ground. If the circuit tests normal, replace
the K20 Engine Control Module. |
- Test for less than 5 Ω between the signal circuit
at the harness connector from G18 High Pressure Fuel Pump
terminal 2 and the signal circuit at the K20 Engine
Control Module terminal 5.
| ⇒ |
If greater than the specified range, test the
signal circuit for an open circuit. If the circuit tests normal,
replace the K20 Engine Control Module. |
- Inspect and repair one of the following
conditions:
High Pressure
| • |
Fuel injection pump stuck open |
| • |
Fuel rail pressure regulator stuck closed |
| • |
Restricted fuel injector |
- If all circuit tests normal, replace the G18 High
Pressure Fuel Pump.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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