If simulation function of WOS or equivalent is used:

Crank the engine and verify that EGR valve operation (initial operation) sound is heard.
- If the operation sound is not heard, connect the WDS or equivalent to the DLC-2 and verify that the DTC P0403 is shown. Perform the DTC inspection. (See DTC TABLE .)
Start the engine run it at idle.
Increase the step value of EGR valve from 0 to 52 using SEGR PID of simulation function.
Operate the EGR valve and inspect if the engine speed becomes unstable or the engine stalls.
- If the engine speed will not change, proceed to following.
1. Stop the engine.
2. Remove the EGR valve.
3. Connect the EGR valve connector.
4. Turn the ignition switch to the ON position.
5. Increase the step value of EGR valve from 0 to 52 using SEGRP PID.
6. Verify that the EGR valve operates according to SEGRP PID.
  - If the EGR valve is operated, clean the EGR valve and EGR gas passage.
  - If the EGR valve will not operate, replace the EGR valve.
Start the engine and warm it up completely.
Access the following PIDs.
- ECT, RPM, SEGRP, APP1, APP2, TP, VSS
Idle the vehicle and verify that the SEGRP value is 0.
Put the vehicle drive.
Depress the accelerator pedal and verify that the SEGRP value is increased.
- If the SEGRP value will not increase, inspect the VSS, TP and ECT PIDs.
  (See PCM INSPECTION .)
Stop the vehicle and verify that the SEGRP value is returned to 0.