Circuit/System Testing

2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2007 Pontiac Torrent and 2007 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
  1. Test for less than 1 ohm of resistance between the DLC ground circuit terminal 5 and ground.
    • If greater than 1 ohm, test the ground circuit for open/high resistance.
  2. Ignition OFF, disconnect the harness connector (splice pack comb) at SP 200. Install a 3-amp fused jumper wire between pin A and pin M of SP 200, harness side.
  3. Ignition ON, with a scan tool, attempt to communicate with the BCM. Communication should be available.
    • If no communication, test the following circuits: serial data circuit for a short to ground, a short to voltage or an open/high resistance between the BCM and DLC, BCM voltage inputs for open/high resistance or short to ground, BCM grounds for open/high resistance. If the circuits test normal, replace the BCM.
  4. Install another 3-amp fused jumper wire to pin A of SP 200, harness side.
  5. Use the other end of the jumper wire to connect all other pins, harness side, one at a time and verify that low speed communication remains available to the BCM.
    • If low speed communication is interrupted after connecting an individual module at SP 200, test the serial data circuit between SP 200 and the last module connected for a short to ground and short to voltage. If the circuit tests normal, replace the module that caused no communication.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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