P1DBD

P1DBD-FUEL PRESSURE SENSOR RATIONALITY

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:
At idle, the rate of change in fueling with respect to the rate of change of pressure is below the calibrated fail high threshold or above the calibrated fail low threshold while the monitor was running.





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

Diagnostic Test

1. ACTIVE DTC

NOTE: If a 5-Volt reference DTC is present, repair that DTC before proceeding with this test.

NOTE: If DTCs P018B, P018C or P018D are present, repair that DTC before proceeding with this test.

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

Did the DTC return?

Yes

- Go To 2

No

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

2. FUEL RAIL PRESSURE SENSOR
1. Perform the diagnostic procedure for CHECKING THE FUEL DELIVERY SYSTEM. Checking The Fuel Delivery System (Hard Start).

Were there any repairs made based on the results of CHECKING THE FUEL DELIVERY SYSTEM?

Yes.

- Repair is complete.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No.

- Replace the Fuel Rail Pressure Sensor.
- Go To 3

3. POWERTRAIN CONTROL MODULE
1. Let the engine run until it reaches normal operating temperature.
2. Using the scan tool, record any DTC's.

Did this DTC return?

Yes

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

No

- Repair is complete.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.