DTC P0400 - EGR Function

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. See Fig 1. If vacuum is not present, go to next step. If vacuum is present, inspect EGR valve and EGR Backpressure Transducer (EGR-BPT) valve. See SYSTEM/COMPONENT TESTS article. Replace EGR valve and/or EGR-BPT valve if necessary and perform FINAL CHECK.
Check EGR Valve & EVAP Canister Purge Control Solenoid - Start engine and allow to idle. Turn ignition off. Wait for at least 5 seconds. Turn ignition on while listening to EGR and EVAP canister purge control solenoid. Replace solenoid valve if it does not click. If solenoid valve clicks, go to next step.
Remove EGR valve and EVAP canister control solenoid. Apply battery voltage to terminals No. 1 and 2. See Fig 2. With battery voltage applied, air should pass between port "A" and "B". Air should not pass between port "A" and "C". With no voltage applied, air should pass between port "A" and "C". Air should not pass between port "A" and "B". Replace EGR and canister control solenoid valve if not as specified. If solenoid valve is okay, go to next step.

Check Component

Measure resistance of EGR temperature sensor. See EGR TEMPERATURE SENSOR RESISTANCE table. Check ECM connector terminals for corrosion or damage. Repair or replace if necessary and perform FINAL CHECK.

EGR TEMPERATURE SENSOR RESISTANCE

Temperature - °F (°C)

⁽²⁾ Ohms

32 (0)

7.9-9.7

122 (50)

.57-70

212 (100)

.08-1.0

⁽¹⁾	Heat sensor in water and measure resistance across sensor terminals.

⁽²⁾	Megohms are given.

Fig 1: DTC P0400, Checking Vacuum Source To EGR Valve (G20)

Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 2: DTC P0400, Checking EGR & Canister Control Solenoid Valve (G20)

Courtesy of NISSAN MOTOR CO., U.S.A.