P018B

DTC P018B-P018D

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P018B
- Fuel Pressure Sensor Performance

DTC P018C
- Fuel Pressure Sensor Circuit Low Voltage

DTC P018D
- Fuel Pressure Sensor Circuit High Voltage

Diagnostic Fault Information






Circuit/System Description

The fuel pressure sensor is located on the fuel line. The fuel pressure sensor monitors the fuel pressure in the fuel line. The fuel pump control module monitors the voltage signal from the fuel pressure sensor.

Conditions for Running the DTC

* The engine is running.

* DTC P018C, P018D, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active.

* DTC P0641 has not failed this ignition cycle.

* Fuel pump control is enabled and the fuel pump control state is normal.

* The engine has been running for at least 5 seconds.

Conditions for Setting the DTC

The fuel pump control module does not detect a change in the fuel pressure of at least 30 kPa (4.4 psi) when the fuel pump is operating. The fuel pressure sensor performance diagnostic provides a means to detect fuel pressure sensor output that is stuck within the normal operating range of the sensor.

Action Taken When the DTC Sets

DTC P018B, P018C and P018D are Type A DTCs.

Conditions for Clearing the DTC

DTC P018B, P018C and P018D are Type A DTCs.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views A/C Compressor Clutch

Description and Operation

Fuel System Description Fuel System Description

Electrical Information Reference

* Circuit Testing Circuit Testing

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Connector Repairs Connector Repairs

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Programming and Relearning for scan tool information

Circuit/System Testing

Note: Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC P018B resets before proceeding with the circuit system testing. If the DTC does not reset, refer to diagnostic aids.

1. Ignition OFF, disconnect the harness connector at the B47 fuel pressure sensor.

2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohms between the low reference circuit terminal 2 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.

3. Ignition ON, test for 4.8-5.2 V between the B47 fuel pressure sensor 5 V reference circuit terminal 3 and ground.

• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.

• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.

4. Verify the scan tool fuel pressure sensor voltage is less than 1 V.

• If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.

5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the 5 V reference circuit terminal 3. Verify the scan tool fuel pressure sensor voltage is greater than 4.8 V.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.

6. If all circuits test normal, replace the B47 fuel pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Fuel Pressure Sensor Replacement - Fuel Feed Pipe Fuel Pressure Sensor Replacement - Fuel Feed Pipe

* Control Module References Programming and Relearning for fuel pump control module replacement, programming and setup