DTC P0400 - EGR FUNCTION Nissan 240SX S14

1. Check Vacuum Source To EGR Valve Start engine and bring to operating temperature. With engine speed at about 2000 RPM, disconnect vacuum hose to EGR valve. (Scheme 32) If vacuum is not present, go to next step. If vacuum is present, inspect EGR valve and EGRC-BPT valve. See procedures in the «SYSTEM/COMPONENT TESTS»(ref-17826) article. Replace EGR valve and/or EGRC-BPT valve if necessary and perform «FINAL CHECK»(ref-17825-S20538276422000122900000).
2. Check Component Ensure vacuum hose to EGR valve is not clogged or cracked. Start engine and allow to idle. Turn ignition off. Wait for at least 3 seconds and turn ignition on. While listening to EGRC valve, depress and release accelerator pedal. Replace solenoid valve if it does not click. If solenoid valve clicks, go to next step.
3. Remove EGRC valve. Apply battery voltage and ground to terminals No. 1 and 2. (Scheme 33) With battery voltage applied, air should pass between ports "A" and "B". Air should not pass between ports "A" and "C". With no voltage applied, air should pass between ports "A" and "C". Air should not pass between ports "A" and "B". Replace EGRC valve if not as specified. If solenoid valve is okay, go to next step.
4. Check carbon canister for damage or clogging. Measure resistance of EGR temperature sensor. See «SYSTEM/COMPONENT TESTS»(ref-17826) article. Check ECM pin terminals for corrosion or damage. Repair or replace if necessary and perform «FINAL CHECK»(ref-17825-S20538276422000122900000).

Scheme 32

Scheme 33