Test H: Barometric Pressure Sensor: Testing

WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: The Powertrain Control Module (PCM) harness connectors must be properly seated and the connector latch properly attached to eliminate possible driveability concerns or a no-start condition. Installing PCM connectors on an angle may cause a bad connection, misdiagnosis and damaged components. Install the connector on where the lever pivots and seats itself. Apply light pressure to get the connector into position on the PCM lever to fully seat the connector.

NOTE: When the PCM engine harness connector is disconnected additional DTCs will be set. All DTCs must be cleared before returning the vehicle to service.

1) Preliminary Diagnosis For DTCs P0107 & P0108

Perform the visual inspection. Connect the scan tool. Retrieve and record all DTCs. Record freeze frame data. Clear all DTCs. Perform the KOEO ON-DEMAND SELF-TEST under QUICK TEST. Are DTCs P0107 or P0108 present? If yes, for P0107, go to next step. For P0108, go to step 6). If no, unable to duplicate condition. Check for loose connections, damaged or corroded pins. Wiggle harness attempting to recreate fault. See TROUBLE SHOOTING - NO CODES - 6.0L DIESEL article, if a driveability concern exists.

2) DTC P0107

Possible causes are:
- Signal circuit short to ground.
- VREF circuit open.
- Faulted BARO sensor.
- Faulted PCM.
Key off. Disconnect BARO sensor electrical connector. Key on. Measure voltage between VREF and SIG RTN circuits at the BARO connector terminals No. 2 and 1. See Figure. Is the VREF voltage between 4.5 and 5.5 volts? If yes, go to next step. If no, go to TEST B: REFERENCE VOLTAGE to diagnosis VREF and SIG RTN.

3) Induce Opposite DTC

Key off. Install a jumper wire between BARO sensor electrical connector terminals No. 2 and 3. Key on. Perform the KOEO ON-DEMAND SELF-TEST under QUICK TEST. Is DTC P0108 present? If yes, install a new BARO sensor. Restore the vehicle. Clear DTCs and retest the system. If no, go to next step.

4) Check Signal Circuit For A Short To Ground

Key off. Disconnect the PCM body harness electrical connector C1381A. Measure the resistance between BARO sensor connector terminal No. 3 and ground. Is the resistance greater than 10,000 ohms? If yes, go to next step. If no, repair short to ground in signal circuit. Restore the vehicle. Clear DTCs and retest the system.

5) Check Signal Circuit For An Open

Measure resistance between BARO sensor electrical connector terminal No. 3 and PCM body harness connector C1381A terminal No. 38. See CONTROL MODULE CONNECTOR IDENTIFICATION . Is the resistance less than 0.5 ohm? If yes, install a new PCM. Restore the vehicle. Clear DTCs and retest the system. If no, repair open in signal circuit. Restore the vehicle. Clear DTCs and retest the system.

6) DTC P0108

Possible causes are:
- Circuit short to voltage.
- Open in signal return circuit.
- Faulted BARO sensor.
- Faulted PCM.
Key off. Induce the opposite DTC. Disconnect the BARO sensor. Key on. Perform the KOEO ON-DEMAND SELF-TEST under QUICK TEST. Is DTC P0107 present? If yes, install a new BARO sensor. Restore the vehicle. Clear DTCs and retest the system. If no, go to next step.

7) Check Signal Circuit For A Short To Voltage

Key off. Disconnect the PCM body harness electrical connector C1381A. Key on. Measure the voltage between BARO sensor connector terminal No. 3 and ground. See Figure. Is the voltage greater than 0.2 volt? If yes, repair short to voltage in the BARO sensor signal circuit. Restore the vehicle. Clear DTCs and RETEST the system. If no, go to next step.

8) Check Signal Return Circuit For An Open

Key off. Measure the resistance between the BARO sensor connector terminal No. 1 and PCM body harness connector C1381A terminal No. 33. See CONTROL MODULE CONNECTOR IDENTIFICATION . Is the resistance less than 0.5 ohm? If yes, install a new PCM. Restore the vehicle. Clear DTCs and retest the system. If no, repair open in the signal return circuit. Restore the vehicle. Clear DTCs and retest the system.