Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0087: Fuel Rail Pressure (FRP) Too LowDTC P0088: Fuel Rail Pressure (FRP) Too High
Diagnostic Fault Information
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Fuel Rail Pressure Sensor 5-Volt Reference Circuit | P0192, P02E8, P0409, P0462, P0642, P2453, P2454, P2564 | P0192 | -- |
Fuel Rail Pressure Sensor Signal Circuit 1 | P0192 | P0193 | P0193 |
Fuel Rail Pressure Sensor Signal Circuit 2 | P0192 | P0193 | P0193 |
Fuel Rail Pressure Sensor Signal Circuit 1 and 2 | P0192 | P0193 | P0193 |
Fuel Rail Pressure Sensor Ground Circuit | -- | P0193 | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: 25 MPa | |||
Fuel Rail Pressure Sensor 5-Volt Reference Circuit | 0.0 MPa | 0.0 MPa | -- |
Fuel Rail Pressure Sensor Signal Circuit 1 | 0.0 MPa | 246.6 MPa | 246.6 MPa |
Fuel Rail Pressure Sensor Signal Circuit 2 | 0.0 MPa | 246.6 MPa | 246.6 MPa |
Fuel Rail Pressure Sensor Signal Circuit 1 and 2 | 0.0 MPa | 246.6 MPa | 246.6 MPa |
Fuel Rail Pressure Sensor Ground Circuit | -- | 246.6 MPa | -- |
Circuit/System Description
| • | The fuel injection pump supplies high pressure fuel to the fuel injection rails, then to the fuel injectors through high pressure pipes. |
| • | The fuel rail pressure (FRP) sensor is a four wire sensor mounted in the fuel injection rail. The FRP sensor uses a 5-volt reference circuit, a signal circuit 1, a signal circuit 2, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine. |
Conditions for Running the DTC
P0087
DTCs P0091, P0092, P0192, P0193, P0642 and P0643 are not set.
P0088
| • | DTCs P0091, P0092, P0192, P0193, P0642 and P0643 are not set. |
| • | The ignition is ON for longer than 2 seconds. |
| • | The battery voltage is between 10-16 volts. |
Conditions for Setting the DTC
P0087
The ECM detects fuel pressure more than 175 MPa.
P0088
The ECM detects that the fuel rail pressure is momentarily more than 208 MPa.
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
P0087
| • | When ambient temperatures are below 0°C (32°F), the fuel tank pickup screen may be iced over from water in the fuel tank. |
| • | When power enhancing devices have been attached to the fuel rail pressure sensor circuits, this DTC may set and adversely effect the fuel system components. |
| • | The fuel temperature may stay high enough to thin the fuel and cause this DTC to set. |
| • | A sticking FRP regulator may cause this DTC to set. |
| • | Air in fuel line will cause this DTC to set. |
P0088
| • | Driveability concerns may not occur with this DTC present. |
| • | If the fuel system pressure is actually too high, a fuel knock and smoke condition will exist. |
| • | A sticking FRP regulator may cause this DTC to set. |
| • | Air in fuel line will cause this DTC to set. |
Reference Information
Schematic Reference
Connector End View Reference
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
Verify the integrity of the fuel system and fuel rail pressure sensor by inspecting for the following conditions:
| • | Damaged components |
| • | Loose or improper installation |
Circuit/System Testing
P0087
- If DTC P0089, P0091, P0092, P0192 or P0193 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Attempt to start the engine.
- With the engine idling or at an idle, command the fuel pressure control with a scan tool. Observe the Actual Fuel Rail Pressure parameter. The actual fuel pressure should be the same as the commanded pressure.
| ⇒ | If the engine does not start, refer to Engine Cranks But Does Not Run . |
| ⇒ | If the Actual Fuel Rail Pressure is not same as the commanded pressure, refer to Diagnostic Aids. |
P0088
- Start the engine and operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- Observe the Actual Fuel Pressure parameter with a scan tool. The actual pressure should be 25 MPa with the engine idling at operating temperature.
- Change the fuel pressure with a scan tool, incrementing through the entire fuel pressure range. The fuel pressure should increment and stabilize through the entire fuel pressure range, with the actual and desired fuel pressure within 2 MPa (290 psi) of each other.
- Test the fuel pressure regulator (FPR) solenoid control circuit and the FPR solenoid supply voltage circuit for high resistance.
| ⇒ | If the pressure difference between the actual and desired pressure are more than 2 MPa (290 psi), replace the fuel pressure regulator. |
| ⇒ | If all circuits test normal, refer to Diagnostic Aids. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
