P0400
SYSTEM DESCRIPTION
This system cuts and controls vacuum applied to the EGR valve to suit engine operating conditions. This cut-and-control operation is accomplished through the ECM and the EGRC-solenoid valve. When the ECM detects any of the following conditions, current does not flow through the solenoid valve. This causes the port vacuum to be discharged into the atmosphere. The EGR valve remain closed.
- Low engine coolant temperature
- Engine starting
- Engine stopped
- Engine idling
- Excessively high engine coolant temperature
- Mass air flow sensor malfunction
- Low vehicle speed or high vehicle speed
- TCS is operating
COMPONENT DESCRIPTION
Exhaust gas recirculation (EGR) valve
The EGR valve controls the amount of exhaust gas routed to the intake manifold. Vacuum is applied to the EGR valve in response to throttle valve opening. The vacuum controls the movement of a taper valve connected to the vacuum diaphragm in the EGR valve.
EGRC-solenoid valve
The EGRC-solenoid valve responds to signals from the ECM. When the ECM sends an ON (ground) signal, the coil in the solenoid valve is energized. The signal reaches to the EGR valve. When the ECM sends an OFF signal, a plunger will then move to cut the vacuum signal from the intake manifold collector to the EGR valve.
Consult-II Reference Value In Data Monitor Mode:
ECM Terminals And Reference Value:
ON BOARD DIAGNOSIS LOGIC
If the absence of EGR flow is detected by EGR temperature sensor under the condition that calls for EGR, a low-flow malfunction is diagnosed.
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a safe speed.
NOTE:
- If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
- P0400 will not be displayed in the "SELF-DIAG RESULTS" mode with CONSULT-II even though the DTC work support test result is "NG".
TESTING CONDITION:
For best results, perform at a temperature above 5 °C (41 °F).
With Consult
1. Turn ignition switch "ON"
2. Check "COOLAN TEMP/S" in "DATA MONITOR" mode witch CONSULT-II.
Confirm COOLAN TEMP/S value is within the range listed below.
COOLANT TEMP/S: Less than 40 °C (104 °F)
If the value is out of range, park the vehicle in a cool place and allow the engine temperature to stabilize. Do not attempt to lower the coolant temperature with a fan or means other than ambient air. Doing so may produce an inaccurate diagnostic result.
3. Select "EGR SYSTEM P0400" of "EGR SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT-II.
4. Touch "START".
5. Start engine (TCS switch "OFF") and let it idle. When the engine coolant temperature reaches 70 °C (158 °F), immediately go to the next step.
6. Accelerate vehicle to a speed of 40 km/h (25 MPH) once and then stop vehicle.
If "COMPLETED" with "OK" appears on CONSULT-II screen, go to step 9.
If "COMPLETED" does not appear on CONSULT-II screen, go to the following step.
7. Check the output voltage of "THRTL POS SEN" at closed throttle position.
8. When the following conditions are met, "TESTING" will be displayed on the CONSULT-II screen. Maintain the conditions until "TESTING" changes to "COMPLETED". (It will take approximately 30 seconds or more.)
CMPS-RPM (POS): 1,200 - 2,000 rpm
Vehicle speed: 10 km/h (6 MPH) or more
B/FUEL SCHDL: 3.3 - 4.5 msec
THRTL POS SEN: X - (X +0.53) V
X = Voltage value measured at step 7
Selector lever: Suitable position
If "TESTING" is not displayed after 5 minutes, retry from step 2.
9. Make sure that "OK" is displayed after touching "SELF- DIAG RESULTS". If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE".
OVERALL FUNCTION CHECK
Use this procedure to check the overall EGR function. During this check, a 1st trip DTC might not be confirmed.
Without Consult
1. Lift up drive wheels.
Start engine (TCS switch "OFF") and warm it up to normal operating temperature.
2. Shift to "D" position.
3. Check the EGR valve lifting when rewing engine from idle up to 3,000 rpm.
EGR valve should lift up and down without sticking.
4. Check voltage between EGR temperature sensor harness connector terminal (1) and ground at idle speed.
Less than 4.5 V should exist.
5. Turn ignition switch "OFF".
6. Check harness continuity between EGR temperature sensor harness connector terminal (2) and ECM terminal (129).
Continuity should exist.
7. Perform "COMPONENTS INSPECTION", "EGR temperature sensor".
8. If NG, go to "DIAGNOSTIC PROCEDURE".
EC-EGRC1-01:
EC-EGRC1-01 Connector View:
WIRING DIAGRAM
Super Multiple Junction (SMJ) Terminal Arrangement (B3, D1, D21, E66, M4, M6, M11, M12, M45, N1):
Super Multiple Junction (SMJ) Terminal Arrangement (B4, B101, E70, E81, F63, M3, M49, M50):
Fuse Block - Junction Block (J/B) Terminal Arrangement (B1, B2, E61, E62, E63, E64, M1):
Part 1:
Part 2:
DIAGNOSTIC PROCEDURE
COMPONENT INSPECTION
EGR valve
Apply vacuum to EGR valve vacuum port with a hand vacuum pump.
EGR valve spring should lift.
Check for sticking.
If NG, repair or replace EGR valve.
EGRC-solenoid valve
Check air passage continuity.
With Consult
Perform "EGRC SOLENOID VALVE" in "ACTIVE TEST" mode.
OR
Without Consult
Check solenoid valve, following the table as shown:
If NG or operation takes more than 1 second, replace the solenoid valve.
EGR temperature sensor
Check resistance change and resistance value.
If NG, replace EGR temperature sensor.
EGRC-BPT valve
1. Plug one of two ports of EGRC-BPT valve.
2. Vacuum from the other port and check for leakage while applying a pressure above 0.981 kPa (100 mmH2O, 3.94 inH2O) from under EGRC-BPT valve.
3. If a leakage is noted, replace the valve.