Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

P0335

  1. Disconnect the CKP sensor.
  2. Test for less than 1 ohm between low reference circuit terminal 2 on the ECM side of the connector and ground.
    • If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 on the ECM side of the connector and ground.
    • If less than the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 on the ECM side of the connector and ground.
    • If less than the specified range, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    • If greater than the specified range, test the affected signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Ignition OFF, connect a 3A fused jumper wire to the CKP signal circuit terminal 1 on the ECM side of the connector.
  6. Ignition ON, momentarily touch the end of the fused jumper wire to ground. The crank signal present and the engine RPM parameters on the scan tool should change.
    • If the crank signal present and the engine RPM does not change, replace the ECM.
  7. Ignition OFF, inspect the wiring harness for any damage, opens, or shorts.
    • If the circuits test normal replace the CKP sensor.
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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.