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Electronic Control Module (ECM) Power & Ground Circuit Test

  1. Turn ignition on. Measure voltage between ground and ECM harness connector terminals No. 38 (Red/Black wire) and No. 47 (Red/Black wire). See Fig 1 . ECM is located behind glove box. 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 fusible link box, next to battery. Check continuity between ECM harness connector terminals No. 38 (Red/Black wire), No. 47 (Red/Black wire), and ECM relay connector terminal No. 5 (Red/Black wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, check harness and connectors between ECM and ECM relay.
  4. Measure voltage between ground and ECM relay harness connector terminals No. 1 (Red wire) and No. 3 (Red wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 25-amp fusible link. Check harness and connectors between ECM relay and battery.
  5. Check voltage between ground and ECM harness connector terminal No. 46 (Yellow wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check 25-amp fusible link. Also check harness and connectors between ECM and battery.
  6. Check continuity between ground and ECM harness connector terminals No. 39 (Black/Red wire) and No. 48 (Black/Red wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open harness or connectors.
  7. Check continuity between ECM harness connector terminal No. 4 (White/Green wire) and ECM relay harness connector terminal No. 2 (White/Green wire). Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open harness between ECM harness connector and ECM relay harness connector.
  8. Turn ignition on. Measure voltage between ground and ECM harness connector terminal No. 36 (Blue/Yellow wire). Battery voltage should be present. If battery voltage is present, check ECM relay. See RELAYS  under RELAYS & SOLENOIDS. If relay is okay, check ECM terminals and ECM harness connector terminals for damage or corrosion. If battery voltage is not present, check harness and connectors.
Fig 1: ECM Connector Terminals (As Viewed From Wiring Harness Side)
G95E31504Courtesy of NISSAN MOTOR CO., U.S.A.
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