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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 271 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING - 3.8L)EMISSION SYSTEMS & SUBSYSTEMSEVAPORATIVE EMISSION SYSTEM CLEANINGINSPECTION PROCEDURE
1999 GMC Forward Control 5.7 R, Automatic
Inspection Procedure
1999 GMC Forward Control 5.7 R, AutomaticSECTION Inspection Procedure
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Use the EVAP Pressure/Purge Diagnostic Station (J 41413) to provide a clean, dry, low pressure gas source. DO NOT substitute any other pressurized gas source. Damage may result to the EVAP system.
- Turn ignition switch to OFF position.
- Remove the EVAP canister purge valve.
- Lightly tap the EVAP canister purge valve on a hard surface.
- Check for carbon particles exiting either of the vacuum ports.
- If no carbon particles were detected, but a blockage was detected during a diagnostic procedure, install the original EVAP canister purge valve and continue with the cleaning procedure.
- If carbon particles are found during the inspection procedure, replace the EVAP canister purge valve and continue with the cleaning procedure.
- If a diagnostic procedure directed you to replace the EVAP canister purge valve and no carbon particles were detected, replace the EVAP canister purge valve and return to diagnostic procedure.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.