Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Verification
2009 Chevrolet Tahoe Base, 4.8 CSECTION Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2010 GMC Yukon XL, 2010 GMC Yukon, 2010 Chevrolet Tahoe, 2010 Chevrolet Suburban, and 2010 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- The engine oil level and the oil pressure are critical to the correct operation of the camshaft position (CMP) actuator system. Verify that the engine has the correct oil level and the correct oil pressure before continuing with this diagnostic. Refer to Oil Pressure Diagnosis and Testing .
- If a crankshaft or camshaft position sensor DTC is set, the Camshaft Position Actuator output control will not function.
- Ignition ON, observe the scan tool DTC information. Verify that none of the following DTCs are set. DTC P0335, P0336, P0340, P0341, P0521, P0522, P0523, P1516, P2101, P2119, or P2176.
- If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
- Command the camshaft position actuator solenoid to 20° with a scan tool. The Desired Camshaft Position parameter should match the Camshaft Position parameter.
- Observe the Camshaft Position Variance parameter with a scan tool. The Camshaft Position Variance will increment for several seconds, until the Camshaft Position value matches the Desired Camshaft Position value. The Camshaft Position Variance value should return to 0°.
- Operate the vehicle within the Conditions for Running the DTC, to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Fame/Failure Records Data List.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.