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.
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HOMESERVICE MANUALSCHEVROLET2006CHEVY EXPRESS G2500, VAN CARGO, 6.6 2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1574 (HYBRID ENERGY STORAGE SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P1A21CIRCUIT/SYSTEM VERIFICATION
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2
Circuit/System Verification
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Circuit/System Verification
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, observe the hybrid battery contactor system request circuit commanded parameter using a scan tool. The contactor system request circuit commanded should be 30 percent.
- Ignition ON, observe the DTC information with a scan tool. DTC P1A21 should not set.
- Operate the vehicle within the Conditions for Running the DTCs. You may also operate the vehicle within the conditions that you observed from the Freeze Fame/Failure Records data.
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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.