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 G3500, VAN PASSENGER EXTENDEDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 329 (HYBRID ENGINE CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P2797CIRCUIT/SYSTEM TESTINGPWM INPUT FAULT
2008 Chevrolet Chevy Express G3500, Van Passenger Extended
PWM Input Fault
2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION PWM Input Fault
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect PIM connector X1.
- Ignition ON, test for 11-13V on the Trans. Aux. Oil Pump Control circuit from PIM connector X1 terminal 5 and chassis ground.
- If less than the specified range, test the control circuit for an open or short to ground. If the circuit tests normal, replace the ATFP Control Module.
- Pre-Adjust the J 38522 variable signal generator to 50 percent duty cycle @ 250 Hz.
- Connect the J 38522
variable signal generator to the Trans. Aux. Oil Pump Control circuit, from the PIM connector X1 terminal 5 and ground and listen for ATFP motor operation.
- If pump operation is audible, replace the PIM.
- If pump operation is not audible, continue with Circuit/System Testing.
- Ignition OFF, disconnect the ATFP control module connector X1.
- Ignition ON, test for 0V on the Trans. Aux. Oil Pump control circuit from PIM connector X1 terminal 5 and chassis ground.
- If greater than the specified range, test the control circuit for a short to voltage.
- If equal to the specified range, replace the ATFP control module.
IMPORTANT:
Only connect the J 38522
to the ATFP control circuit when adjusted to 50 percent duty cycle. Duty cycles of less than 50 percent may damage the ATFP pump assembly.
RENDER: 1.0x
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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.