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 VARIANT/TRIMSECTION 14 (ENGINE CONTROL SYSTEM & FUEL SYSTEM - 6.6L (LMM) - DTC P0700 TO DTC P2463)DTC P2459COMPONENT TESTING
2008 Chevrolet Chevy Express G3500, Van Passenger Extended
Component Testing
2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Component Testing
WARNING: This page is about a different variant/trim than selected.
IMPORTANT:
- You must perform the Circuit/System Testing in order to verify the integrity of the exhaust differential pressure sensor circuits before proceeding with Component Testing.
- Perform the Repair Verification after completing the Component Testing.
- Ignition OFF, remove the exhaust pressure differential pressure sensor.
- Install a 3A fused jumper wire between the 5-volt reference circuit terminal 3 and the corresponding terminal of the differential sensor. Install a jumper wire between the low reference terminal 1 of the sensor and ground.
- Install a jumper wire between the low reference circuit terminal 1 of the differential sensor and ground.
- Install a jumper wire at terminal 2 of the differential sensor.
- Connect a DMM between the jumper wire from terminal 2 of the differential sensor and ground.
- Ignition ON, with the J 23738-A
or J 35555
connected to the pressure sensor rear pressure port, slowly apply vacuum to the sensor while monitoring the voltage between the signal terminal 2 and the low reference terminal 1. See Special Tools
. The voltage should vary between 4.8-0.4 volts without any spikes or dropouts.
- If the voltage is erratic, replace the differential pressure sensor.
RENDER: 1.0x
NO RELATED
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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.