Circuit/System Verification

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.

Ignition OFF, inspect the engine wiring harness carrying the CMP sensor circuits for the following conditions:
- Close routing of aftermarket electrical equipment
- Close to solenoids, motors, and relays.

If any of these are determined to be a possible source of electrical interference, correct any wire harness routing or component placement conditions.
Start the engine. Using the live plot function on the scan tool, select the CMP sensor parameter. Change the minimum spec to 400, and the maximum spec to 4,000 RPM. Select the CKP sensor parameter. Change the minimum spec to 600, and the maximum spec to 3,300 RPM.
Observe the scan tool.
Quickly accelerate and release the accelerator pedal several times. Do not accelerate pass 3,200 RPM. The graphed lines on the live plot display should track together across the screen.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.