Inspection Procedure 2

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

Data Link Connector Circuit Part 1:

Data Link Connector Circuit Part 2:

CIRCUIT OPERATION
- A diagnostic output is made from the ECM or the PCM (terminal No. 74) 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: )
- Open or shorted data link connector circuit, harness damage or connector damage.

DIAGNOSIS

STEP 1. Check harness connector C-137 at ECM or C-138 at PCM for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 2.

NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 2. Check for open circuit, short circuit to ground and harness damage between data link connector C-14 (terminal No. 7) and ECM connector C-137 or PCM connector C-138 (terminal No. 74).

NOTE: Check harness after checking intermediate connectors C-101 and C-124. If intermediate connectors are damaged, repair or replace them. 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.