Page 739 of 3051
Wiring DiagramNLEC0231MODELS WITH ECM IN ENGINE COMPARTMENTNLEC0231S01
YEC664
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG18DE
Wiring Diagram
EC-314
Page 740 of 3051
MODELS WITH ECM IN CABINNLEC0231S02
YEC884
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG18DE
Wiring Diagram (Cont'd)
EC-315
Page 742 of 3051

4 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between
ECM terminal 8 and EGR volume control valve terminal 1,
ECM terminal 9 and EGR volume control valve terminal 4,
ECM terminal 17 and EGR volume control valve terminal 3,
ECM terminal 18 and EGR volume control valve terminal 6.
Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit, short to ground or short to power in harness connectors.
5 CHECK EGR PASSAGE
Check EGR passage for clogging and cracks.
OK or NG
OK©GO TO 6.
NG©Repair or replace EGR passage.
6 CHECK EGR TEMPERATURE SENSOR
Refer to ªCOMPONENT INSPECTIONº, EC-392.
OK or NG
OK©GO TO 7.
NG©Replace EGR temperature sensor.
7 CHECK EGR VOLUME CONTROL VALVE
Refer to ªCOMPONENT INSPECTIONº, EC-318.
OK or NG
OK©GO TO 8.
NG©Replace EGR volume control valve.
8 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-145.
©INSPECTION END
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG18DE
Diagnostic Procedure (Cont'd)
EC-317
Page 747 of 3051
Wiring DiagramNLEC0510MODELS WITH ECM IN ENGINE COMPARTMENTNLEC0510S01
YEC665
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG18DE
Wiring Diagram
EC-322
Page 748 of 3051
MODELS WITH ECM IN CABINNLEC0510S02
YEC885
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG18DE
Wiring Diagram (Cont'd)
EC-323
Page 749 of 3051

Diagnostic ProcedureNLEC0511
1 CHECK POWER SUPPLY
1. Disconnect EGR volume control valve harness connector.
2. Turn ignition switch ªONº.
3. Check voltage between terminals 2, 5 and ground with CONSULT-II or tester.
SEF782Z
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+15A fuse
+Harness connectors E76, F36
+Harness connectors M72, F44 (where fitted)
+Harness connectors M11, E106 (LHD models) (where fitted)
+Harness connectors M78, E120 (RHD models) (where fitted)
+Harness for open or short between fuse and ECM relay
+Harness for open or short between EGR volume control valve and ECM relay
+ECM relay
©Repair harness or connectors, or replace fuse or ECM relay.
3 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between
ECM terminal 8 and EGR volume control valve terminal 1,
ECM terminal 9 and EGR volume control valve terminal 2,
ECM terminal 17 and EGR volume control valve terminal 3,
ECM terminal 18 and EGR volume control valve terminal 4.
Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit, short to ground or short to power in harness connectors.
4 CHECK EGR VOLUME CONTROL VALVE
Refer to ªCOMPONENT INSPECTIONº, EC-326.
OK or NG
OK©GO TO 5.
NG©Replace EGR volume control valve.
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG18DE
Diagnostic Procedure
EC-324
Page 755 of 3051

5 CHECK INJECTORS
1. Refer to Wiring Diagram for Injectors, EC-495.
2. Stop engine and then turn ignition switch ªONº.
3. Check voltage between ECM terminals 101, 103, 105 and 107 and ground with CONSULT-II or tester.
SEF075X
Battery voltage should exist.
OK or NG
OK©GO TO 6.
NG©Perform ªDiagnostic Procedureº INJECTOR, EC-497.
6 CHECK IGNITION SPARK
1. Disconnect ignition coil assembly from rocker cover.
2. Connect a known good spark plug to the ignition coil assembly.
3. Place end of spark plug against a suitable ground and crank engine.
4. Check for spark.
SEF575Q
OK or NG
OK©GO TO 7.
NG©Check ignition coil, power transistor and their circuits. Refer to EC-500.
7 CHECK INJECTOR
1. Turn ignition switch ªOFFº.
2. Remove injector assembly. Refer to EC-44.
Keep fuel hose and all injectors connected to injector gallery.
3. Disconnect camshaft position sensor harness connector.
4. Turn ignition switch ªONº.
Make sure fuel does not drip from injector.
OK or NG
OK (Does not drip)©GO TO 8.
NG (Drips)©Replace the injector(s) from which fuel is dripping.
DTC P0420 THREE WAY CATALYST FUNCTIONQG18DE
Diagnostic Procedure (Cont'd)
EC-330
Page 759 of 3051
Wiring DiagramNLEC0253MODELS WITH ECM IN ENGINE COMPARTMENTNLEC0253S01
YEC666
DTC P0443 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
(CIRCUIT)
QG18DE
Wiring Diagram
EC-334