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HOMESERVICE MANUALSISUZU2006ASCENDER S, 5.3 M, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 591 (ENGINE CONTROL SYSTEM & FUEL SYSTEM - 4.2L - DTC P0366 T0 DTC P2544)DTC P0685 OR P0690CIRCUIT/SYSTEM TESTING
2006 Isuzu Ascender S, 5.3 M, 4WD

Circuit/System Testing

2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2009 GMC Envoy and 2009 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the powertrain relay using the J 43244:  Pliers.
  2. Ignition ON, verify that a test lamp does not illuminate between the ignition circuit terminal 87 and ground.
    • If the test lamp illuminates, test the ignition circuit for a short to voltage.
  3. Ignition OFF, verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  5. Disconnect the X2 harness connector at the ECM.
  6. Test for less than 2 ohms between ground and the ECM terminal 73 X2.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition ON, verify that a test lamp illuminates between connector terminal 19 X1 and ground.
    • If the test lamp does not illuminate, test the circuit for an open/high resistance and a short to ground. If the circuit tests normal and its fuse is open, replace the ECM.
  8. Ignition OFF, connect the harness connector at the ECM.
  9. Ignition ON, connect a jumper wire between the B+ circuit terminal 30 and the ignition circuit terminal 87. Verify that the EC Ignition Relay Feedback Signal parameter indicates B+ voltage.
    • If the parameter does not indicate B+ voltage, test the ignition circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  10. Ignition OFF, allow the ECM to completely power down.
  11. Verify that a test lamp does not illuminate between the B+ circuit terminal 86 and the control circuit terminal 85.
    • If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  12. Remove the test lamp.
  13. Ignition ON, verify the scan tool EC Relay Ckt. Short Volts Test Status parameter is OK.
    • If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  14. Install a 3A fused jumper wire between the control circuit terminal 85 and the B+ circuit terminal 86. Verify the scan tool EC Relay Ckt. Short Volts Test Status parameter is Fault.
    • If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  15. If all circuits test normal, replace the powertrain relay.
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