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Home >> Mitsubishi >> 2000 >> Mirage LS, 4D Sedan >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Circuit Tests >> Scan Tool Will Not Communicate >> No Communication With ECM

No Communication With ECM

  1. Check connectors and wiring between ECM and OBD-II Data Link Connector (OBD-II DLC). If wiring and connectors are okay, check MFI relay. See FUEL PUMP RELAY & MFI RELAY under RELAYS under MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article. If problem exists, replace MFI relay. If MFI relay is okay, go to next step.
  2. Remove MFI relay. Check voltage between ground and MFI relay 4-pin connector terminals No. 3 and 4. If battery voltage exists at each terminal, go to next step. If battery voltage does not exist at each terminal, check connectors and wiring between MFI relay and battery. If problem exists, repair connector or wiring as necessary. If connectors and wiring are okay, check ignition switch.
  3. Reinstall MFI relay. Disconnect ECM 26-pin connector B-40. Turn ignition on. Check voltage between ground and ECM connector B-40 terminals No. 12 and 25. If battery voltage exists at each terminal, go to next step. If battery voltage does not exist at either terminal, repair appropriate wire between MFI relay and ECM.
  4. Turn ignition off. Check continuity between ground and ECM connector B-40 terminals No. 13 and 26. If continuity exists between ground and each terminal, go to next step. If continuity does not exist between ground and each terminal, repair open in appropriate wire between ECM and ground. Ground points are located behind right kick panel and top right side of firewall.
  5. Disconnect ECM 22-pin connector B-37. Turn ignition on. Check voltage between ground and ECM connector B-37 terminal No. 80. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in wire between battery and ECM.
  6. Check ECM connectors B-37 and B-40. If problem exists, repair ECM connectors as necessary. If ECM connectors are okay, replace ECM.
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