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 MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 2105 (TRAILER BRAKE CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B3894 (GASOLINE WITHOUT LY6)CIRCUIT/SYSTEM TESTING
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
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.
- Verify that DTC B3445, C0277, C0297, or C0890 are not set.
- If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Ignition OFF, disconnect the harness connector of the fuel pump/trailer brake control module.
- Ignition ON, test for greater than 11 V between the IGN 1 voltage circuit terminal 15 and ground.
- If less than the specified voltage, test the IGN 1 voltage circuit for a short to ground or an open/high resistance. If the circuit test normal and the MISC - IGN fuse is open, test the signal circuit terminal 37 for a short to ground. If the circuit tests normal, test or replace the RUN/CRANK relay.
- If all the circuits test normal, replace the fuel pump/trailer brake control module.
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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.