DTC P0400 (EGR) - Exhaust Gas RECIRCULATION (EGR) Flow Malfunction

NOTE: Refer to illustration for connector and terminal identification. See Figure -Figure .

Ensure transmission type (A/T only). Check for DTC P0105, P0106, P0403 or P01102. Perform relevant testing for codes shown. Manually check EGR valve diaphragm for sticking.
WARNING: Use extreme caution when checking EGR valve. Valve will be extremely hot and can cause severe burns. If no DTC is displayed, go to next step.
Check vacuum hoses for disconnection, cracks, clogging or other damage. Check and repair if necessary:
- Two lines of pipes and hoses running between throttle body and back pressure transducer (BPT)
- Pipe and hose line connecting BPT and EGR solenoid valve
- Hose between EGR solenoid valve and EGR valve
- BPT pressure transmitting hose
If leakage is not found, go to next step.
Turn ignition to OFF. Connect SSM. Turn ignition to ON. If EGR solenoid valve does not make a clicking sound, replace EGR solenoid valve. If EGR solenoid valve does make a clicking sound, turn ignition to OFF. Disconnect connector from EGR solenoid valve. From an external 12 volt source, connect negative leg to one terminal of EGR solenoid valve and positive leg to the other.
CAUTION: DO NOT use vehicle battery as 12 volt source. Vehicle electrical system may be damaged.

Start engine. Open throttle valve 5-10 degrees and visually check EGR valve operation. 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 the CONFIRMATION OF ACTUAL DRIVING PATTERN . If malfunction is again detected in CONFIRMATION OF ACTUAL DRIVING PATTERN, check for clogging in gas outlets of intake manifold or cylinder head (check by breathing into outlets). If clogged, repair or replace intake manifold or cylinder head. and return to CONFIRMATION OF ACTUAL DRIVING PATTERN . If not clogged, replace EGR valve and go to CONFIRMATION OF ACTUAL DRIVING PATTERN .