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 MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 234 (ENGINE CONTROLS - SELF-DIAGNOSTICS)DIAGNOSTIC TESTSDTC P0401: EGR SYSTEM - INSUFFICIENT FLOWDIAGNOSTIC PROCEDURES
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8
Diagnostic Procedures
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Cadillac Seville and 2003 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
- Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
- Are there any MAP DTCs set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
- Inspect the exhaust system for modification of original installed parts or leaks. Repair the exhaust system as necessary if you locate a problem. Did you find and correct the condition? If yes, go to step 7. If no, go to next step.
- Check the EGR valve gasket and pipes for leaks. If you locate a problem, clean or replace the EGR system components as necessary. See EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you find and correct the condition? If yes, go to step 7. If no, go to next step.
- Remove the EGR valve. See EGR VALVE
under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Visually and physically inspect the following items for a leak or a restriction:
- The EGR pintle.
- The EGR valve passages.
Did you find and correct the condition? If yes, go to step 7. If no, go to next step.
- Remove the EGR inlet pipe from the exhaust manifold. Inspect the manifold EGR ports and the EGR inlet pipe for blockage caused by excessive deposits or other damage. Correct the condition as necessary if a problem is found. Did you find and correct the condition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
- Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running DTC. Does the DTC run and pass? If yes, go to step 2. If no, go to next step.
- Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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.