Inspection Procedure 2

INSPECTION PROCEDURE 2: Scan Tool Communication with ECM [M/T] or PCM [A/T] 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 [M/T] or the PCM [A/T] (terminal No. 15) to the diagnostic output terminal (terminal No. 7) of the data link connector.

COMMENT
- No power supply to ECM [M/T] or PCM [A/T].
- Defective ground circuit of ECM [M/T] or PCM [A/T].
- Defective ECM [M/T] or PCM [A/T].
- Improper communication line between ECM [M/T] or PCM [A/T] and scan tool.

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

DIAGNOSIS

STEP 1. Check harness connector B-18 at ECM [M/T] or PCM [A/T] for damage.






Q: Is the harness connector in good condition?

YES : Go to Step 2.

NO : Repair or replace it. Refer to general (electrical), Harness Connector Inspection. 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-125 (terminal No. 7) and ECM [M/T] or PCM [A/T] connector B-18 (terminal No. 15).









NOTE: Check harness after checking intermediate connectors C-21. If intermediate connector C-21 is damaged, repair or replace it. Refer to general (electrical), Harness Connector Inspection. Then check that the malfunction is eliminated.

Q: Is the harness wire in good condition?

YES : Refer to MFI, INSPECTION PROCEDURE 28 -Power Supply System and Ignition Switch-IG System. Inspection Procedure 28

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