Pinpoint Test A: Pcm Does Not Respond To The Scan Tool
WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
- A1 POWERTRAIN CONTROL/EMISSIONS DIAGNOSIS (PC/ED) MANUAL PINPOINT TEST QA VERIFICATION CHECK
- Verify that pinpoint test QA has been carried out.
- Has pinpoint test QA been carried out?
- YES : Go to A2.
- NO : REFER to the Introduction - Gasoline Engines , Section 5, pinpoint test QA to diagnose no communication with the PCM.
- A2 CHECK THE HS-CAN TERMINATION RESISTANCE
- Key in OFF position.
- Disconnect the battery ground cable.
- Measure the resistance between the data link connector (DLC) C251-6, circuit VDB04 (WH/BU), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
- Is the resistance between 54 and 66 ohms?
NOTE: Failure to disconnect the battery will result in false resistance readings.Courtesy of FORD MOTOR CO.
- A3 CHECK THE HS-CAN CIRCUITS BETWEEN THE DLC AND THE PCM FOR AN OPEN
- Measure the resistance between the PCM C175b-2, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the PCM C175b-3, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
- Are the resistances less than 5 ohms?
Courtesy of FORD MOTOR CO.
Courtesy of FORD MOTOR CO.
- YES : Go to A4.
- NO : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.
- A4 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS . CONNECT all modules. CONNECT the battery ground cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
- NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CONNECT the battery ground cable. CLEAR the DTCs. REPEAT the network test with the scan tool.