Inspection Procedure 2

INSPECTION PROCEDURE 2: Scan Tool Communication with ECM or PCM Is Not Possible

Data Link Connector Circuit:

Connectors:

Connectors:

CIRCUIT OPERATION
- A diagnostic output is made from the ECM (terminal No.85) or PCM (terminal No.85) to the diagnostic output terminal (terminal No.7) of the data link connector.

COMMENT
- No power supply to ECM or PCM .
- Defective ground circuit of ECM or PCM .
- Defective ECM or PCM .
- Improper communication line between ECM or PCM and scan tool.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of ECM or PCM power supply circuit.
- Malfunction of the ECM or PCM .
- Open circuit between ECM or PCM and data link connector.

DIAGNOSIS

Connectors:

STEP 1. Check connector C-122 at ECM or connector C-119 at PCM for damage.

Q: Is the connector in good condition?

YES: Go to Step 2.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.

Connectors:

STEP 2. Check for open circuit, short circuit to ground and harness damage between data link connector C-26 (terminal No.7) and ECM connector C-122 (terminal No.85) or PCM connector C-119 (terminal No.85) .

NOTE: Check harness after checking intermediate connectors C-140 and C-25. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.

Q: Is the harness wire in good condition?

YES: Refer to INSPECTION PROCEDURE 29 - Power Supply System and Ignition Switch - IG System.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.