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Home >> Mitsubishi >> 1999 >> Montero Sport ES 2WD L4-2.4L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Data Link Connector >> Testing and Inspection >> Scan Tool Communication With PCM/ECM Is Not Possible
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Scan Tool Communication With PCM/ECM Is Not Possible

CIRCUIT OPERATION
- A diagnostic output is made from the ECM (terminal 62) to the diagnostic output terminal (terminal 7) of the data link connector.
- When diagnostic test mode control terminal (terminal 1) of the data link connector is grounded, the ECM (terminal 56) changes to the diagnostic test mode.

COMMENT
One of the following causes may be suspected:
- No power supply to ECM.
- Defective ground circuit of ECM.
- Defective ECM.
- Improper communication line between ECM and scan tool.

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




WIRING DIAGRAM




CONNECTORS

DIAGNOSIS







STEP 1. Check the harness wire between the data link connector C-69 and the ECM connector C-55.

NOTE: After inspecting the intermediate connectors C-10 and C-16, inspect the wire. If the intermediate connectors C-10 and C-16 are damaged, repair or replace them. Refer Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.

If the wire between the data link connector C-69 and the ECM connector C-55 is not damaged, go to Step 2.
If the wire between the data link connector C-69 and the ECM connector C-55 is damaged, repair it. Then confirm that the malfunction symptom is eliminated.




STEP 2. Check harness connector C-55 at the ECM for damage.
If harness connector C-55 is damaged, repair or replace it. Refer Harness Connector Inspection.
If harness connector C-55 is in good condition, refer to INSPECTION PROCEDURE 28 - Power Supply System and Ignition Switch-IG System.
Then confirm that the malfunction symptom is eliminated.
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