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 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, disconnect the harness connector at the B26 crankshaft position sensor.
  2. Ignition OFF and all vehicle systems OFF, it may take 2 minutes for all vehicle systems to power down, test for less than 1 Ξ© between the crankshaft position low reference circuit, terminal B, 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 K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the crankshaft position 5 V reference circuit, terminal C and ground.
    • If less than the specified range, test the 5 V reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM.
    • If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, test for 4.8-5.2 V between the crankshaft position signal circuit terminal A and ground.
    • If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Ignition OFF, connect a 3 A fused jumper wire to the crankshaft position signal circuit terminal A.
  6. Ignition ON, momentarily touch the other end of the fused jumper wire to the battery negative post. The Crankshaft Position Active counter, should increment.
    • If the Crankshaft Position Active counter increments, test or replace the B26 crankshaft position sensor.
    • If the Crankshaft Position Active counter does not increment, replace the K20 ECM.
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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.
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