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Home >> Mitsubishi >> 2002 >> Lancer ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Circuit Check >> Scan Tool Will Not Communicate >> No Communication With ECM Or PCM
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No Communication With ECM Or PCM

  1. Turn ignition off. Check ECM (M/T) or PCM (A/T) harness connectors for loose, damaged or corroded terminals. ECM or PCM is located behind glove compartment. See Figure . Repair as necessary. If problem does not exist, go to next step.
  2. Using a DVOM, check for open or short to ground in OBD-II DLC terminal No. 7 (Orange wire) and ECM harness connector C-117 terminal No. 62 (M/T) or PCM harness connector C-116 terminal No. 85 (A/T). See Figure and Figure . Repair circuit as necessary. If problem does not exist, go to next step.
  3. Remove MFI relay from underhood fuse/relay block (located near air cleaner box). Check MFI relay connector for loose, damaged or corroded terminals. Repair or replace as necessary. If problem does not exist, go to next step.
  4. 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 problem does not exist, reinstall MFI relay and go to next step.
  5. Turn ignition on, with engine off. Measure voltage between ground and MFI relay connector terminals No. 1 (Black/Yellow wire) and No. 2 (Black/Yellow wire). If battery voltage is present at both terminals, go to next step. If battery voltage is not present at either or both terminals, repair Black/Yellow wire between underhood fuse/relay block and power supply.
  6. Turn ignition off. Disconnect ECM or PCM harness connectors. Check connector terminals. Repair or replace as necessary. If problem does not exist, go to next step.
  7. Turn ignition on, with engine off. Check voltage between ground and ECM harness connector C-115 terminal No. 82 (M/T) or PCM harness connector C-116 terminal No. 98 (A/T). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, repair Black/Red wire between ECM or PCM harness connector and ignition switch.
  8. Check voltage between ground and ECM harness connector C-115 terminal No. 80 (M/T) or PCM harness connector C-118 terminal No. 66 (A/T). If battery voltage is present, go to next step. If battery voltage is not present, repair Red/Black wire between ECM or PCM and power supply.
  9. Turn ignition off. Disconnect ECM harness connector C-121 (M/T) or PCM harness connector C118 (A/T). Check resistance between ECM harness connector C-121 terminals No. 13 and No. 26 (M/T) or PCM harness connector C-118 terminals No. 42 and No. 48 (A/T). If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, repair open in circuit.
  10. Check voltage between ground and ECM harness connector C-119 terminal No. 38 (M/T) or PCM harness connector C-118 terminal No. 49 (A/T). If battery voltage is present, go to next step. If battery voltage is not present, repair open in circuit to power supply.
  11. Connect a jumper wire between ECM harness connector C-119 terminal No. 38 (M/T) or PCM harness connector C-118 terminal No. 49 (A/T). Turn ignition on, with engine off. Using DVOM, check voltage between ECM harness connector C-118 terminals No. 41 and No. 47 (A/T) or PCM harness connector C-121 terminals No. 12 and No. 25. If battery voltage is present, replace ECM or PCM. If battery voltage is not present, check harness connectors for damage. Repair or replace as necessary. If harness connectors are okay, check for open in circuit to MFI relay.
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