DTC P0400: EGR FUNCTION Infiniti I30 I

1. Check Power Supply - Turn ignition off. Turn ignition on. Measure voltage between EGR temperature sensor connector terminal No. 1 (Blue/Orange wire) and ground. Voltage should be less than 4.5 volts. Measure voltage between ECM connector terminals No. 25 and 59. see scheme 4 Voltage should be less than 2.24 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair harness as necessary.
2. Check Input Signal - Turn ignition off. Measure voltage between EGR temperature sensor connector terminal No. 2 and ECM connector terminal No. 43. If continuity is present, go to next step. If continuity is not as present, repair harness or connectors as necessary.
3. Check Vacuum Source To EGR Valve - Start engine and bring to operating temperature. With engine speed at 2000-4000 RPM, disconnect vacuum hose to EGR valve. If vacuum is not present, check vacuum hose for restriction. If no faults are found, go to next step. If vacuum is present, inspect EGR valve. See «SYSTEM/COMPONENT TESTS»(ref-18021) article. Service or replace components if necessary and perform FINAL CHECK.
4. Check EGRC Solenoid - Turn ignition on. Check operating sound of EGRC solenoid while disconnecting and reconnecting EGRC solenoid harness connector. If solenoid is not functioning properly, repair or replace solenoid as required. If solenoid is functioning properly, go to next step.
5. Disconnect EGRC solenoid. Apply battery voltage and ground to terminals No. 1 and 2. (Scheme 23) 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 solenoid if airflow is not as specified. If solenoid is okay, check vacuum hoses for restrictions or misrouting.
6. Check EGR Temperature Sensor - Ensure sensor is not damaged or contaminated. Check ECM and EGR temperature sensor harness connectors for damage, corrosion or pushed-out pins. Repair if necessary. If no problems are found, ensure ignition is off. Measure resistance between EGR temperature sensor connector terminals. With temperature at 212°F (100°C), resistance should be.08-.10 megohms. Resistance should increase as temperature decreases. If resistance is not as specified, replace EGR temperature sensor. If resistance is as specified, disconnect harness connectors in circuit and check for damage or corrosion. If fault is still present, go to DTC P0402: EGR CONTROL BACKPRESSURE TRANSDUCER (EGRC-BPT) VALVE.

Scheme 23