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Home >> Mazda >> 2002 >> MPV ES >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC U0101: Pcm Cannot Receive Any Messages From TCM >> Diagnostic Procedures

Diagnostic Procedures

  1. Record freeze frame data. Check for service bulletins and on-line information. Repair as necessary. After repair, go to next step.
  2. Verify Related Pending Code Or Stored DTCs -  Turn ignition on, engine off. If DTC U0073 is not present, go to next step. If DTC U0073 is present, go to DTC U0073: CAN BUS OFF .
  3. Inspect Poor Connection Of TCM Connector -  Turn ignition off. Disconnect TCM 24-pin harness connectors. Check for damaged, loose or corroded terminals. If no problem is found, go to next step. If problem is present, repair terminal or connector as necessary. After repair, go to step  8.
  4. Check CAN Communication Line For Short To Ground -  Check continuity between following:
    • Ground and TCM 24-pin harness connector terminal No. 2J (Red/Black wire). See Figure.
    • Ground and TCM 24-pin harness connector terminal No. 2M (Yellow/Red wire).

    If continuity is not present, go to next step. If continuity is present, repair suspect wire for short to ground. See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. After repair, go to step  8.

  5. Check CAN Communication Line For Short To Power -  Measure voltage between following terminals:
    • Ground and TCM 24-pin harness connector terminal No. 2J (Red/Black wire).
    • Ground and TCM 24-pin harness connector terminal No. 2M (Yellow/Red wire).

    If continuity is not present, go to next step. If continuity is present, repair suspect wire for short to power. After repair, go to step  8.

  6. Inspect Poor Connection Of PCM Connector -  Turn ignition off. Disconnect PCM 104-pin harness connector. Check for damaged, loose or corroded terminals. If no problem is found, go to next step. If problem is present, repair terminal or connector as necessary. After repair, go to step  8.
  7. Check CAN Communication Line For Open -  With PCM 104-pin harness connector disconnected, check for continuity between following terminals:
    • TCM 24-pin harness connector terminal No. 2J and PCM 104-pin harness connector terminal No. 49 (Red/Black wire).
    • TCM 24-pin harness connector terminal No. 2M and PCM 104-pin harness connector terminal No. 50 (Yellow/Red wire).

    If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire PCM 104-pin harness connector and appropriate TCM 24-pin harness connector. After repair, go to next step.

  8. Verify Trouble Shooting Of DTC U0101 Completed -  Using scan tool, clear DTC. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Turn ignition off. Start engine. Recheck DTC. If DTC U0101 is present, replace PCM. After repair, go to next step. If DTC U0101 is not present, go to next step.
  9. Verify After Repair Procedure -  Using scan tool, perform after repair procedure. See AFTER REPAIR PROCEDURE . If DTC is not present, testing is complete. If any DTC is present, go to appropriate test for diagnosis and repair.
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