Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the B23 camshaft position sensor.
- Ignition OFF and all vehicle systems OFF. It may take 2 minutes for all vehicle systems to power down, test for less than 5 Ω on the 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.
- Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A 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.
- Ignition ON, test for 4.8-5.2 V between the signal circuit terminal C 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.
- Ignition OFF, connect a 3A fused jumper wire to the signal circuit terminal C.
- Ignition ON, momentarily touch the other end of the 3 A fused jumper wire to the battery negative post. The scan tool CMP Active counter should increment.
- If the parameter does not increment, replace the K20 ECM.
- If all circuits test normal, test or replace the B23 camshaft position sensor.