Inspection Procedure 2
Scan Tool Communication with ECM or PCM Is Not Possible.
Connectors:
CIRCUIT OPERATION
- A diagnostic output is made from the ECM (terminal 85)
- When diagnostic test mode control terminal (terminal 1) of the data link connector is grounded, the ECM (terminal 84)
COMMENT
- No power supply to ECM
- Defective ground circuit of ECM
- Defective ECM
- Improper communication line between ECM
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of ECM
- Malfunction of the ECM
- Open circuit between ECM
DIAGNOSIS
STEP 1. Check connector C-122 at ECM
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.
STEP 2. Check for open circuit, short circuit to ground and harness damage between data link connector C-26 terminal 1 and ECM connector C-122 terminal 84
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: Go to Step 3.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 3. Check for open circuit, short circuit to ground and harness damage between data link connector C-26 terminal 7 and ECM connector C-122 terminal 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.