Circuit/System Testing

2006 Isuzu Ascender S, 5.3 M, 4WDSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC.
  2. IMPORTANT: A short to voltage on the signal circuit of certain components may cause this DTC to set.
  3. Ignition ON, measure for 4.8-5.2 volts between one of the 5-volt reference circuits and ground.
    • If the voltage is less than the specified value, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
    • If the voltage is greater than the specified value, test for a short to voltage on all the 5-volt reference circuits. If all circuits test normal, replace the ECM.
  4. Connect each component associated with the 5-volt reference circuit, one at a time, while monitoring the voltage. Verify the voltage remains between 4.8-5.2 volts.
    • If the voltage display is not within the specified range when a component is connected, test the signal circuit for a short to voltage. If all circuits test normal, replace the component.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.