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Home >> Mitsubishi >> 2000 >> Montero Sport ES >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Circuit Tests >> Scan Tool Will Not Communicate >> No Communication With PCM

No Communication With PCM

  1. Check wires and intermediate connectors between OBD-II Data Link Connector (OBD-II DLC) and Powertrain Control Module (PCM) 28-pin connector C-91. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Check PCM connector C-91. If problem exists, repair connector. If problem does not exist, go to next step.
  3. Remove and check MFI relay. See RELAYS under MOTORS, RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article. Replace MFI relay as necessary. If MFI relay is okay, go to next step.
  4. Connect 20-ohm resistor in series with positive lead of Digital Volt-Ohmmeter (DVOM) and MFI relay connector terminal No. 3. Connect negative lead of DVOM to ground. Turn ignition on and check current. Also check current between ground and MFI relay connector terminal No. 4. Current should be 500 milliamps or more. If current is within specification, go to next step. If current is not within specification, check wire(s) between MFI relay and fusible link. Repair as necessary.
  5. Turn ignition off. Install MFI relay. Disconnect PCM 28-pin connector C-91. Turn ignition on. Check voltage between ground and PCM connector C-91 terminal No. 98. If battery voltage exists, go to next step. If battery voltage does not exist, check wire between ignition switch and PCM. Repair as necessary. If wiring is okay, check ignition switch.
  6. Turn ignition off. Disconnect PCM 26-pin connector C-90. Check voltage between ground and PCM connector C-90 terminal No. 66. If battery voltage exists, go to next step. If battery voltage does not exist, check wire between battery and PCM. Repair as necessary.
  7. Check resistance between ground and PCM connector C-90 terminals No. 42 and 48. If resistance is zero ohms, go to next step. If resistance is more than zero ohms, repair wire between ground and PCM.
  8. Connect jumper wire between ground and PCM connector C-90 terminal No. 49. MFI relay should audibly click. Then measure voltage between ground and PCM connector C-90 terminals No. 41 and 47. 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 PCM.
  9. Check all PCM connectors. Repair as necessary. If connectors are okay, replace PCM.
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