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.
Diagnostic Procedures
1999 Chevrolet Suburban C2500, 6.5 FSECTION Diagnostic Procedures
- Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
- If DTC P0412 or P0418 is also present, diagnose DTC. If DTCs are not present, go to next step.
- Check AIR pump fuse. If fuse is okay, go to next step. If fuse is open, go to step 11.
- Turn ignition on, with engine off. Using scan tool, enable AIR pump. If pump turns on, go to step 8. If AIR pump does not turn on, go to next step.
- Turn ignition off. Disconnect AIR pump relay. Turn ignition on, engine off. Using test light connected to ground, probe power supply circuit to relay. If test light illuminates, go to next step. If test light does not illuminate, go to step 17.
- Turn ignition off. Reconnect AIR pump relay. Disconnect AIR pump harness connector. Connect test light between battery negative terminal and probe AIR pump harness connector terminal "A". Turn ignition on, engine off. Using scan tool, enable AIR pump. If test light illuminates, go to next step. If test light does not illuminate, go to step 18.
- Connect test light between AIR pump harness connector terminals "A" and "C". Using scan tool, enable AIR pump. If test light illuminates, go to step 27. If test light does not illuminate, go to step 19.
- Turn ignition off. Disconnect AIR pump harness connector. Using test light connected to negative battery terminal, probe AIR pump harness connector terminal "B". Turn ignition on, with engine off. Using scan tool, enable AIR pump. If test light illuminates, go to next step. If test light does not illuminate, go to step 20.
- Turn ignition off. Reconnect AIR pump harness connector. Disconnect AIR pump outlet hose. Turn ignition on. Using scan tool, enable AIR pump. If air is present at pump outlet, go to next step. If air is not present, go to step 27.
- Check for restriction or blockage in AIR hoses/pipes between AIR pump and to where system branches to both sides of engine. Repair as necessary. After repairs, go to step 29. If AIR hoses/pipes are not restricted or blocked, go to next step.
- Turn ignition off. Remove AIR pump relay, AIR solenoid relay and AIR pump bleed valve solenoid. Install new fuse(s). Turn ignition on, with engine off. Recheck fuse(s). If fuse blows, go to step 21. If fuse does not blow, go to next step.
- Install AIR solenoid relay. Using scan tool, enable AIR pump relay/solenoid relay. Recheck fuse(s). If fuse blows, go to step 22. If fuse is okay, go to next step.
- Install AIR pump harness connector. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 28. If fuse is okay, go to next step.
- Disconnect AIR pump harness connector. Install AIR pump relay. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 23. If fuse is okay, go to next step.
- Install AIR pump harness connector. Using scan tool, enable AIR pump. Recheck fuse(s). If fuse blows, go to step 28. If fuse is okay, go to next step.
- Install EVAP canister purge valve pump harness connector. Using scan tool, enable EVAP canister purge valve. Recheck fuse(s). If fuse blows, go to step 24. If fuse is okay, see DIAGNOSTIC AIDS .
- Repair open circuit between fuse and relay. After repairs, go to step 29.
- Check for continuity between AIR pump and AIR pump relay. If circuit is open, repair as necessary. After repairs, go to step 29. If circuit is okay, go to step 25.
- Repair faulty ground connection or open AIR pump ground circuit. After repairs, go to step 29.
- Check for continuity between AIR pump and AIR pump relay. If circuit is open, repair as necessary. After repairs, go to step 29. If circuit is okay, go to step 26.
- Repair short to ground in ignition feed circuit between fuse and relay. After repairs, go to step 29.
- Repair short to ground between AIR solenoid relay and AIR pump. After repairs, go to step 29.
- Repair short to ground between AIR pump relay and AIR pump. After repairs, go to step 29.
- Replace AIR bleed valve solenoid. After replacing solenoid, go to step 29.
- Replace AIR pump solenoid. After replacing solenoid, go to step 29.
- Repair AIR solenoid relay. After replacing relay, go to step 29.
- Check AIR pump electrical connections. Repairs as necessary. After repairs, go to step 29. If connections are okay, go to next step.
- Replace AIR pump. After replacing pump, go to next step.
- Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0410. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2.
- Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.
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.