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 10 (ENGINE CONTROL SYSTEM & FUEL SYSTEM - 6.6L (LMM) - DTC P0016 TO DTC P0299)DTC P0087 OR P0088CIRCUIT/SYSTEM TESTINGP0087
2008 Chevrolet Chevy Express G3500, Van Passenger Extended
Circuit/System Testing: P0087
2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION P0087
WARNING: This page is about a different variant/trim than selected.
- If DTC P0090, P0168 or P0191 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- Attempt to start the engine.
- If the engine does not start, refer to Engine Cranks but Does Not Run .
- Install the CH-48027
to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT).
- If more than 5 inches Hg of vacuum was present during engine speed increase, replace the fuel filter and inspect the fuel supply lines for damage between the fuel tank and the fuel injection pump.
- If no restriction was found, test for high fuel return flow. Refer to Fuel System Diagnosis - High Pressure Side .
- With the engine idling or at an idle, command the fuel pressure control to 180 MPa (26,106 psi) with a scan tool. Observe the Actual Fuel Rail Pressure parameter. The actual fuel pressure should be the same as the commanded pressure.
- If the Actual Fuel Rail Pressure is less than 165 MPa (23,931 psi), refer to Fuel System Diagnosis - High Pressure Side .
- Operate the vehicle within the conditions for which the customer complaint occurs while observing the CH-48027
. You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records.
- If the vacuum was more than 12 inches Hg of vacuum at any time in the operating range, inspect for kinked or restricted fuel supply lines.
- Operate the vehicle within the conditions for which the customer complaint occurred. Observe the Actual fuel Rail Pressure and Desired Fuel rail Pressure parameters with a scan tool. Fuel pressures should be the same for both parameters.
- If the Actual Fuel Rail Pressure is less than the Desired Fuel Rail Pressure, refer to Fuel System Diagnosis - High Pressure Side .
- If fuel system tests normal, refer to Diagnostic Aids .
IMPORTANT:
If the fuel temperature is near 121°C (250°F) during the duplication of the complaint, or in the Failure Records for this DTC, inspect for a restriction in the fuel cooler air flow or the fuel heater always ON. Refer to Fuel Heater Always On
.
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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.