DESCRIPTION
Based on the driving conditions, the ECM regulates the volume of exhaust gas that is recirculated to the engine's combustion chambers and thus lowers the combustion temperature to reduce NOx emissions. The ECM monitors signals such as engine speed, coolant temperature, engine load, and vehicle speed. When the EGR permission conditions are fulfilled, the ECM controls the opening of the EGR valve through signals to the EGR stepper motor.
DTC No. | DTC Detection Condition | Trouble Area |
---|---|---|
P0401 | Change in intake manifold pressure is small when the EGR valve is opened and closed during idle fuel cut operation (2 trip detection logic) |
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CONFIRMATION DRIVING PATTERN
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG) and turn the tester on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.
Turn the power switch off and wait for 30 seconds.
Turn the power switch on (IG) and turn the tester on [A].
Put the engine in inspection mode Click here.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more [B].
Tech Tips
The A/C switch and all accessory switches should be off and shift lever in P or N.
Drive the vehicle at 60 km/h (37 mph) for 5 minutes or more [C].
Idle the engine for 30 seconds or more [D].
Accelerate the vehicle at 60 km/h (37 mph) then select the S4 range with the shift lever in S [E].
Perform fuel cut operation for 5 seconds or more, with the accelerator pedal fully released [F].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Tech Tips
When fuel cut is operating, "Idle Fuel Cut" in Data List is ON.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / EGR/VVT Monitor.
Check that the EGR/VVT Monitor is Compl (complete).
Tech Tips
If the EGR/VVT Monitor is Incmpl (incomplete), perform the driving pattern again.
If the EGR/VVT Monitor is still Incmpl (incomplete), perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / DTC / Pending [G].
Read the Pending DTC.
Tech Tips
If a pending DTC is output, the system is malfunctioning.
If a pending DTC is not output, perform the following procedure
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0401.
Check the DTC judgment result.
Tester Display | Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
UNKNOWN |
|
Tech Tips
If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the DTC judgment result is INCOMPLETE or UNKNOWN and no pending DTC is output, accelerate the vehicle again at 60 km/h (37 mph) then select the S4 range with the shift lever in S, perform fuel cut operation for 5 seconds or more with the accelerator pedal fully released, and check the DTC judgment result.
INSPECTION PROCEDURE
Tech Tips
By using the Control the EGR Step Position Active Test, the operation of the EGR valve can be checked.
If the EGR valve is normal and is opened using the Active Test, the Data List value changes as follows.
Data List | Change in Data List when Number of Steps is Increased Using Control the EGR Step Position Active Test |
---|---|
MAP | Pressure rises |
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P0401)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the DTC.
Result | ||||||
---|---|---|---|---|---|---|
|
B |
GO TO DTC CHART Click here |
A |
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Put the engine in inspection mode (maintenance mode) Click here.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
Tech Tips
The A/C switch and all accessory switches should be off.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.
Confirm that the Throttle Idle Position is ON and check the MAP value in the Data List while performing the Active Test.
Note
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.
OK |
---|
MAP change in response to EGR step position when Throttle Idle Position is ON in Data List. |
Standard | ||||||||
---|---|---|---|---|---|---|---|---|
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Tech Tips
While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.
Result | ||||||
---|---|---|---|---|---|---|
|
B |
REPLACE EGR VALVE ASSEMBLY Click here |
A |
INSPECT EGR VALVE ASSEMBLY
Check if the EGR valve are clogged with deposits.
Check if the EGR valve is closed.
OK |
---|
EGR valve is closed and no deposits. |
Result | ||||||
---|---|---|---|---|---|---|
|
B |
CHECK FOR DEPOSIT (INTAKE PORT TO EGR VALVE ASSEMBLY) Click here |
A |
REPLACE EGR VALVE ASSEMBLY
Replace the EGR valve assembly Click here.
NEXT |
CHECK FOR DEPOSIT (INTAKE PORT TO EGR VALVE ASSEMBLY)
Check for exhaust leaks at each connection point.
Check for cracks, damage, and clogs in the pipes between the intake manifold converter and the EGR valve assembly.
This check may require the removal of components.
Check if there is a build-up of deposits in the EGR valve or pipes.
OK |
---|
No deposits |
NG |
REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA |
OK |
CHECK FOR DEPOSIT (EXHAUST MANIFOLD CONVERTER TO EGR VALVE ASSEMBLY)
Check for exhaust leaks at each connection point.
Check for cracks, damage, and clogs in the pipes between the exhaust manifold converter and the EGR valve assembly.
This check may require the removal of components.
Check if there is a build-up of deposits in the EGR valve or pipes.
OK |
---|
No deposits |
NG |
REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA |
OK |
INSPECT EGR COOLER ASSEMBLY
Check for blockage of the EGR cooler assembly.
NG |
REPLACE EGR COOLER ASSEMBLY Click here |
OK |
READ VALUE USING INTELLIGENT TESTER (MANIFOLD ABSOLUTE PRESSURE SENSOR)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAP.
Read the MAP value.
Standard | ||||
---|---|---|---|---|
|
Result | ||||||
---|---|---|---|---|---|---|
|
B |
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here |
A |
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks Click here.
OK |
---|
No leaks in intake system. |
NG |
REPAIR OR REPLACE INTAKE SYSTEM |
OK |
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
Replace the manifold absolute pressure sensor Click here.
NEXT |
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTC Click here.
Turn the power switch off and wait for 30 seconds.
Turn the power switch on (IG) and turn the tester on.
Put the engine in inspection mode Click here.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.
Tech Tips
The A/C switch and all accessory switches should be off and shift lever in P or N.
Drive the vehicle at 60 km/h (37 mph) for 5 minutes or more.
Idle the engine for 30 seconds or more.
Accelerate the vehicle at 60 km/h (37 mph) then select the S4 range with the shift lever in S.
CAUTION:
Strictly observe speed limits and traffic laws when performing the confirmation drive pattern.
Perform fuel cut operation for 5 seconds or more, with the accelerator pedal fully released.
Tech Tips
If the deceleration was not completed, perform the Confirmation Driving Pattern again.
Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.
Read Pending DTC.
If the pending DTC is output, the system is malfunction.
Tech Tips
If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0401.
Check the DTC judgment result.
Tester Display | Description |
---|---|
NORMAL |
|
ABNORMAL |
|
INCOMPLETE |
|
UNKNOWN |
|
Tech Tips
If the judgment result shows ABNORMAL, the system has a malfunction.
If the DTC judgment result is INCOMPLETE or UNKNOWN and no pending DTC is output, accelerate the vehicle again at 60 km/h (37 mph) then select the S4 range with the shift lever in S, perform fuel cut operation for 5 seconds or more with the accelerator pedal fully released, and check the DTC judgment result.
NEXT |
END