Pinpoint Test B: The Pcm Does Not Respond To The Diagnostic Tool

WARNING: This page is about a different car, the 2004 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.

B1 CHECK THE VEHICLE ENGINE

Check the vehicle for engine type.
Is the vehicle equipped with a 2.0L SVT or a 2.3L engine?

Yes

GO to B3.

GO to B2.

B2 CHECK SCP CIRCUITS BETWEEN THE DLC AND THE PCM FOR AN OPEN

Key in OFF position.
Disconnect: PCM C175.
Measure the resistance between the PCM C175 pin 16, circuit 4-EG9 (GY/OG), harness side and the DLC C251 pin 2, circuit 4-EG7 (GY/RD), harness side: and between the PCM C175 pin 15, circuit 5-EG9 (BU/BK), harness side and the DLC C251 pin 10, circuit 5-EG6 (BU), harness side.

Fig 1: Checking SCP Circuits Between The DLC And The PCM For An Open
Courtesy of FORD MOTOR CO.
Are the resistances less than 5 ohms?

Yes

GO to B4.

REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

B3 CHECK CAN CIRCUITS BETWEEN THE DLC AND THE PCM FOR AN OPEN

Key in OFF position.
Disconnect: PCM C175 (2.0L SVT) or C175b (2.3L).
For 2.3L, measure the resistance between the PCM C175b pin 11, circuit 4-EC7 (GY/RD), harness side and the DLC C251 pin 6, circuit 4-EC7 (GY/RD), harness side; and between the PCM C175b pin 23, circuit 5-EC7 (BU/RD), harness side and the DLC C251 pin 14, circuit 5-EC7 (BU/RD), harness side.

Fig 2: Check CAN Circuits Between The DLC And The PCM For An Open 2.3L
Courtesy of FORD MOTOR CO.
For 2.0L SVT, measure the resistance between the PCM C175 pin 50, circuit 4-EC7 (GY/RD), harness side and the DLC C251 pin 6, circuit 4-EC7 (GY/RD), harness side; and between the PCM C175 pin 49, circuit 5-EC7 (BU/RD), harness side and the DLC C251 pin 14, circuit 5-EC7 (BU/RD), harness side.

Fig 3: Check CAN Circuits Between The DLC And The PCM For An Open 2.0L
Courtesy of FORD MOTOR CO.
Are the resistances less than 5 ohms?

Yes

GO to B4.

REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

B4 CHECK FOR CORRECT PCM OPERATION

Disconnect all PCM connectors.
Check for:
- corrosion
- pushed-out pins
Connect all 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 POWERTRAIN CONTROL MODULE (PCM) . CARRY OUT the data link diagnostics test. CLEAR the DTCs. REPEAT the self-test.

The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.