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 MANUALSCHEVROLET2012CHEVY EXPRESS G2500, VAN PASSENGER, 4.8L ENG VIN AREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 820 (WIRING SYSTEMS AND POWER MANAGEMENT - DTC B1370 TO DTC B1475)DTC B1380CIRCUIT/SYSTEM VERIFICATION
2012 Chevrolet Chevy Express G2500, Van Passenger, 4.8L Eng VIN A
Circuit/System Verification
2012 Chevrolet Chevy Express G2500, Van Passenger, 4.8L Eng VIN ASECTION Circuit/System Verification
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- Verify that the following DTCs are not set: U1814, B1428.
- If either of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- With a scan tool, access Body Control Module, Power Mode data display list and compare all parameters listed with the corresponding ignition key position. The PMM Power Mode Parameters table below illustrates the correct state of these input parameters (circuits) in correspondence to the ignition switch position. The circuits which the individual parameters are related to are in parentheses.
PMM Power Mode Parameters
| Ignition Switch Position | Currant Power Mode | Ign. Off/Run/Crank (Off/Run Crank voltage circuit) |
Ignition Accessory/Run (Accessory voltage circuit) |
Ignition Run/Crank (Ignition 1 Voltage circuit) |
|---|---|---|---|---|
| Off Key Out | Off | Key Out/ACC | Inactive | Inactive |
| Off Key IN | Off | Key In/Off | Inactive | Inactive |
| Accessory | Accessory | Key Out/ACC | Active | Inactive |
| Run | Run | Run | Active | Active |
| Start | Crank Request | Crank | Inactive | Active |
- If any parameters are incorrect in any key position, proceed to the Circuit/System Testing or Component Testing below.
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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.