P018D

P018D-FUEL PRESSURE SENSOR CIRCUIT HIGH

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

The Powertrain Control Module (PCM) provides a 5-Volt supply to the Fuel Rail Pressure Sensor (FRPS). The PCM also provides a ground on the sensor return circuit. The Fuel Rail Pressure Sensor provides a signal to the PCM on the Fuel Rail Pressure Sensor Signal circuit. This sensor signal voltage changes based on the pressure in the fuel rail. The PCM will detect a low signal voltage at low rail pressures. The PCM will detect a high signal voltage during high rail pressure conditions. The PCM will light the MIL lamp immediately after the diagnostic runs and fails. During this time the customer may experience a power and or speed derate. The PCM will turn off the MIL light after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
With the ignition on and battery voltage greater than 10.4 Volts.

- Set Conditions:
The circuit voltage to the Powertrain Control Module (PCM) is above a calibrated threshold for a certain period of time.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC

NOTE: If there are any 5-Volt supply DTCs present, diagnose and repair those DTCs before proceeding.

1. Turn the ignition on.
2. With the scan tool, read DTCs.

Is the DTC active?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. CHECK THE (K181) FUEL RAIL PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the FRPS harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (K181) FRPS Signal circuit at the FRPS harness connector.

Is the reading above 5.2 volts?

Yes

- Repair the (K181) Fuel Rail Pressure Sensor Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE (K181) FUEL RAIL PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO THE (F856) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnected PCM C1 harness connector.
3. Measure the resistance between the (K181) FRPS Signal circuit and the (F856) 5-Volt Supply circuit at the FRPS harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 3

No

- Repair the short between the (K181) Fuel Rail Pressure Sensor Signal circuit and the (F856) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. CHECK THE (K181) FUEL RAIL PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K181) FRPS Signal circuit between the FRPS harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the (K181) Fuel Rail Pressure Sensor Signal circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. CHECK THE (K914) SENSOR GROUND FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K914) Ground circuit between the FRPS harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 6

No

- Repair the (K914) Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. CHECK THE FUEL RAIL PRESSURE SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C1 harness connector.
3. Turn the ignition on.
4. While monitoring scan tool, connect a jumper between the (K181) FRPS Signal circuit and the (K914) Sensor Ground circuit at the FRPS harness connector.

NOTE: The P018C-FUEL RAIL PRESSURE SENSOR CIRCUIT LOW DTC should become active or pending with the jumper in place.

Does the DTC display as described above?

Yes

- Replace the Fuel Rail Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Rail Pressure Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Fuel Rail Pressure Sensor and Control Module connectors.
4. Perform any Technical Service Bulletins (TSBs) that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.