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 1682 (ENGINE CONTROLS AND FUEL - 4.3L - DTC P0016 TO DTC P0336)DTC P0102 OR P0103CIRCUIT/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 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
All electrical components and accessories must be turned OFF and allowed to power down.
- Verify the integrity of the air induction system by inspecting for the following conditions:
- Loose or improper installation
- Water intrusion
- Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
- Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal C and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.
- If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal A and ground.
- If less than the specified range, test the signal circuit terminal A for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal A at the MAF/IAT sensor harness connector. See Special Tools . Connect the battery voltage supply to B+. Connect the black lead to ground.
- Set the J 38522 signal to 5 volts, the Frequency to 5K, and the Duty Cycle to Normal. See Special Tools .
- Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,025 Hz.
- If the MAF Sensor parameter is not within the specified range, replace the ECM.
- If all other circuits test normal, replace the MAF sensor.
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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.