P1402
SYSTEM DESCRIPTION
This system controls flow rate of EGR led from exhaust manifold to intake manifold. The opening of the EGR bypass passage in the EGR volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions. The EGR volume control valve remains close under the following conditions.
- Engine stopped
- Engine starting
- Engine idling
- Low engine coolant temperature
- Excessively high engine coolant temperature
- High engine speed
- Wide open throttle
- Low battery voltage
COMPONENT DESCRIPTION
EGR Volume Control Valve
The EGR volume control valve uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECM. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECM does not issue the pulse signal. A certain voltage signal is issued so that the valve remains at that particular opening.
Consult-II Reference Value In Data Monitor Mode:
On Board Diagnosis Logic
If the EGR temperature sensor detects EGR flow under the condition that does not call for EGR, a high-flow malfunction is diagnosed.
Malfunction is detected when EGR flow is detected under condition that does not call for EGR.
NOTE: Diagnosis for this DTC will occur when engine coolant temperature is below 50 to 60 °C (122 to 140 °F). Therefore, it will be better to turn ignition switch "ON" (start engine) at the engine coolant temperature below 30 °C (86 °F) when starting DTC confirmation procedure.
Possible Cause
- Harness or connectors
(EGR volume control valve circuit is open or shorted.)
- EGR volume control valve leaking or stuck open
- EGR temperature sensor
DTC Confirmation Procedure
NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.
TESTING CONDITION:
- Always perform the test at a temperature above -10 °C (14 °F).
- Engine coolant temperature and EGR temperature must be verified in "DATA MONITOR" mode with CONSULT-II before starting DTC WORK SUPPORT test. If it is out of range below, the test cannot be conducted.
COOLAN TEMP/S: -10 to 50 °C (14 to 122 °F)*
EGR TEMP SEN: Less than 4.8 V
If the values are out of the ranges indicated above, park the vehicle in a cool place and allow the engine temperature to stabilize. Do not attempt to reduce the engine coolant temperature or EGR temperature with a fan or means other than ambient air. Doing so may produce an inaccurate diagnostic result.
*: Although CONSULT-II screen displays "-10 to 40 °C (14 to 104 °F)" as a range of engine coolant temperature, ignore it.
WITH CONSULT-II
1. Turn ignition switch "OFF", and wait at least 5 seconds, and then turn "ON".
2. Select "EGR SYSTEM P1402" of "EGR SYSTEM" in "DTC WORK SUPPORT" mode with CONSULT-II.
3. Touch "START".
4. Start engine and let it idle until "TESTING" on CONSULT-II screen is turned to "COMPLETED". (It will take 80 seconds or more.)
If "TESTING" is not displayed after 5 minutes, turn ignition "OFF" and cool the engine coolant temperature to the range of -10 to 50 °C (14 to 122 °F). Retry from step 1.
5. Make sure that "OK" is displayed after touching "SELF-DIAG RESULTS". If "NG" is displayed, refer to "Diagnostic Procedure" below.
WITH GST
1. Turn ignition switch "ON" and select "MODE 1" with GST..
2. Check that engine coolant temperature is within the range of -10 to 50 °C (14 to 122 °F).
3. Check that voltage between ECM terminal 72 (EGR temperature sensor signal) and ground is less than 4.8 V.
4. Start engine and let it idle for at least 80 seconds.
5. Stop engine.
6. Perform from step 1 to 4.
7. Select "MODE 3" with GST.
8. If DTC is detected, go to "Diagnostic Procedure" below.
- When using GST, "DTC Confirmation Procedure" should be performed twice as much as when using CONSULT-II because GST cannot display MODE 7 (1st trip DTC) concerning this diagnosis. Therefore, using CONSULT-II is recommended.
EC-EGRC1-01:
EC-EGRC1-01 Connector View:
ECM Terminals And Reference Value:
Wiring Diagram
Diagnostic Procedure
Diagnostic Procedure Steps 1 - 3:
Diagnostic Procedure Steps 4 - 5:
