Inspection Procedure 2

Scan Tool Communication with PCM Is Not Possible.

Data Link Connector Circuit Part 1:

Data Link Connector Circuit Part 2:

CIRCUIT OPERATION
- A diagnostic output is made from the PCM (terminal No. 15) to the diagnostic output terminal (terminal No. 7) of the data link connector.

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

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

DIAGNOSIS




STEP 1. Check harness connector B-19 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.







STEP2. Check for open circuit, short circuit to ground and harness damage between data link connector C-125 (terminal No. 7) and PCM connector B-19 (terminal No. 15).

NOTE: Check harness after checking intermediate connectors C-29. If intermediate connector C-29 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 28 - Power Supply System and Ignition Switch-IG System. Inspection Procedure 28

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