P0402
DTC P0402 Exhaust Gas Recirculation Flow Excessive DetectedCIRCUIT DESCRIPTION
DTC Detection Condition:
The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the driving conditions, into the intake air mixture to slow down combustion, reduce the combustion temperature and reduce NOx emissions.
The lift amount of the EGR valve is controlled by the vacuum which is regulated by the Duty-VSV operated by the ECM. The lift amount of the EGR valve is detected by the EGR valve position sensor which is mounted on the EGR valve and it provides feedback to the ECM to control the lift amount of the EGR valve in response to the engine operating conditions.
Under the following conditions, the EGR is cut to maintain driveability.
- Before the engine is warmed up
- During deceleration (throttle valve closed)
- Light engine load (very small amount of intake air)
- Engine speed over 4,000 rpm
- Engine idling
Wiring Diagram:
SYSTEM CHECK DRIVING PATTERN
1. Connect the OBD II scan tool or hand-held tester to the DLC3.
2. Start and warm up the engine with all the accessories switched OFF.
3. Run the vehicle at 70 - 90 km/h (43 - 56 mph) for 3 minutes or more.
4. Idle the engine for about 2 min.
. Perform steps (3) and (4) again.
6. Stop the vehicle at a safe place and turn the ignition switch OFF.
7. Perform steps (2) to (5) again.
8. Check the READINESS TESTS mode on the OBD II scan tool or hand-held tester.
If COMPL is displayed and the MIL does not light up, the system is normal.
If INCMPL is displayed and the MIL does not light up, perform steps (2) to (6) several times and check check the READINESS TESTS mode again.
HINT:
INCMPL is displayed when either condition (a) or (b) exists.
a. The system check is incomplete.
b. There is a malfunction in the system.
If there is a malfunction in the system, the MIL lights up after step (7) (2 trip detection logic).
INSPECTION PROCEDURE
HINT:
- If different DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, terminal E2 may be open.
- Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
Step 1 - 2:
Step 3 - 4:
Step 5 - 7:
Step 8 - 9:
Hand-held tester
Step 1 - 3:
Step 4 - 6:
Step 7 - 8:
OBD II scan tool (excluding hand-held tester)