Inspection Procedure 20: EGR Valve (DC Motor) System








OPERATION



  • The electric current from the engine-ECU (terminal No. 121 and No. 122) to the EGR valve (DC motor) (terminal No. 4 and No. 5) is controlled.

FUNCTION



  • Engine-ECU changes current direction according to the Open/Close direction and also changes current to the motor coil in order to the control EGR valve.
  • The engine-ECU performs feedback control over the EGR valve based on the signals from the EGR valve position sensor.

PROBABLE CAUSES



  • Failed EGR valve
  • Open/short circuit or harness damage in EGR valve circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-108 EGR valve connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Connector check: B-16 engine-ECU connector

Q. Is the check result normal?
Go to Step 3 .
Repair or replace the connector.

STEP 3. Check harness between the B-16 (terminal No. 121) engine-ECU connector and B-108 (terminal No. 4) EGR valve connector.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 4 .
Repair the damaged harness wire.

STEP 4. Check harness between B-16 (terminal No. 122) engine-ECU connector and B-108 (terminal No. 5) EGR valve connector.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 5 .
Repair the damaged harness wire.

STEP 5. Replace the EGR valve assembly.

  • After replacing the EGR valve assembly, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU.
The check is end.