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Home >> Nissan-Datsun >> 1995 >> Pathfinder SE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests 3.0L >> Computerized Engine Controls >> Electronic Control Module (ECM) Power & Ground Circuit Test

Electronic Control Module (ECM) Power & Ground Circuit Test

  1. Turn ignition on. Measure voltage between ground and ECM harness connector terminals No. 38 (Black/White wire), No. 47 (Black/White wire), and No. 109 (Black/White wire). See Fig 1 . ECM is located under passenger's seat. Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, go to step 3).
  2. Turn ignition off. Disconnect ECM harness connector. Check continuity between ground and ECM harness connector terminals No. 6 (Black wire), No. 13 (Black wire), No. 107 (Black wire), No. 108 (Black wire), and No. 116 (Black wire). Continuity should exist. If continuity does not exist, repair harness or connectors. If continuity exists, check ECM terminals and ECM harness connector terminals for damage or corrosion.
  3. Turn ignition off. Disconnect ECM harness connector. Disconnect ECM (ECCS) relay. Relay is located in relay box, on right front inner fender panel. Check continuity between ECM harness connector terminals No. 38 (Black/White wire), No. 47 (Black/White wire), No. 109 (Black/White wire), and ECM relay connector terminal No. 5 (Black/White wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, check harness and connectors between ECM and relay.
  4. Measure voltage between ground and ECM relay harness connector terminals No. 2 (White wire) and No. 3 (White wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check Brown fusible link. Check harness and connectors between ECCS relay and battery.
  5. Check continuity between ground and ECM harness connector terminals No. 39 (Black wire) and No. 48 (Black wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open harness or connectors.
  6. Check continuity between ECM harness connector terminal No. 4 (White/Red wire) and ECCS relay harness connector terminal No. 1 (White/Red wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open harness between ECM harness connector and ECCS relay harness connector.
  7. Turn ignition on. Measure voltage between ground and ECM harness connector terminal No. 36 (Black/White wire). Battery voltage should be present. If battery voltage is not present, repair harness and connectors between ECM harness connector and ignition switch. If battery voltage is present, check ECM (ECCS) relay. See RELAYS under RELAYS & SOLENOIDS. If relay is okay, check ECM terminals and ECM harness connector terminals for damage or corrosion.
Fig 1: ECM Connector Terminals (As Viewed From Wiring Harness Side)
G95E31504Courtesy of NISSAN MOTOR CO., U.S.A.
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