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, 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) FRPS 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) FRPS Signal circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE (K181) FRPS SIGNAL CIRCUIT FOR A SHORT TO THE (F856) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect both PCM C1 and C2 harness connectors.
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 below 10k Ohms?

Yes

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

No

- Go To 4

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) FRPS Signal circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. CHECK THE (K914) FUEL RAIL PRESSURE SENSOR GROUND FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K914) FRPS 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 both PCM C1 and C2 harness connectors.
3. Reconnect the FRPS harness connector.
4. Turn the ignition on.
5. With the scan tool, erase DTCs.
6. While monitoring scan tool, connect a jumper between the (K181) FRPS Signal circuit and the (K914) Sensor Ground circuit at the FRPS harness connector.

Does the DTC P018B set?

Yes

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

No

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