| WARNING | Use extreme caution when checking EGR valve. Valve can be extremely hot and cause severe burns. |
- Connect scan tool. Retrieve DTC(s). If DTC P0106, P0107, P0108, P0403, P1102, P1122 or P1421 exist, diagnose affected DTC(s) first. Manually check EGR valve diaphragm for sticking. After checking, go to «CONFIRMATION OF ACTUAL DRIVING PATTERN»(ref-26343-S40608621542001010500000) , clear DTC(s) and retest. If DTC P0400 is only code set, go to next step.
- Check all EGR vacuum hoses for leaks, cracks, clogging or other damage. Check and repair as necessary: Pipes and hoses running between throttle body and Backpressure Transducer (BPT). Pipe and hose line connecting BPT and EGR solenoid valve. Hose between EGR solenoid valve and EGR valve. BPT pressure hose. After checking and repairing, proceed to «CONFIRMATION OF ACTUAL DRIVING PATTERN»(ref-26343-S40608621542001010500000) . If no problems are found, go to next step.
- Turn ignition off. Connect test mode connector (under left side of dash). Turn ignition on. If a clicking is heard from solenoid, go to next step. If no clicking is heard, replace EGR solenoid.
- Check EGR valve by disconnecting EGR solenoid valve connector, then connecting an external 12-volt source (not tested vehicle's battery) to EGR solenoid valve on one terminal and grounding other terminal. Start engine. Open throttle valve 5-10 degrees and visually check EGR valve operation. If EGR valve does not operate, go to next step. If EGR valve operates, malfunction may be due to freezing or clogging by foreign matter. DO NOT replace EGR valve at this point since it may not be faulty. Proceed to «CONFIRMATION OF ACTUAL DRIVING PATTERN»(ref-26343-S40608621542001010500000) . If malfunction is detected again, go to next step.
- If EGR valve does not operate, check for clogging in gas outlets of intake manifold or cylinder head (check by blowing into outlets). If clogged, repair or replace intake manifold or cylinder head and return to «CONFIRMATION OF ACTUAL DRIVING PATTERN»(ref-26343-S40608621542001010500000) . If not clogged, replace EGR valve and go to CONFIRMATION OF ACTUAL DRIVING PATTERN.