Diagnosis Procedure

Regarding Wiring Diagram information, refer to WIRING DIAGRAM .

1. CHECK EPS CONTROL UNIT GROUND CIRCUIT
   
   
   1. Turn ignition switch OFF.
   2. Disconnect EPS control unit harness connector.
   3. Check continuity between EPS control unit harness connector terminal and ground.

      EPS control unit		-	Continuity
      Connector	Terminal
      E23	18	Ground	Yes

   4. Connect EPS control unit harness connector.

   Is the inspection result normal?

   YES 

   GO TO STEP 2  .

   NO 

   Repair open circuit or short to ground or short to power in harness or connectors.

2. CHECK EPS CONTROL UNIT POWER SUPPLY CIRCUIT (1)
   
   
   1. Check voltage between EPS control unit harness connector terminal and ground.

      EPS control unit		-	Voltage (Approx.)
      Connector	Terminal
      M53	4	Ground	0 V

   2. Turn ignition switch ON.
      CAUTION:

      Never start the engine.

   3. Check voltage between EPS control unit harness connector and ground.

      EPS control unit		-	Voltage (Approx.)
      Connector	Terminal
      M53	4	Ground	Battery voltage

   Is the inspection result normal?

   YES 

   GO TO STEP 4  .

   NO 

   GO TO STEP 3  .

3. CHECK EPS CONTROL UNIT POWER SUPPLY CIRCUIT (2)
   
   
   1. Turn ignition switch OFF.
   2. Check the 10A fuse No. 5.
   3. Check the harness for open or short between EPS control unit harness connector M53 terminal 4 and the 10A fuse No. 5.

   Is the inspection result normal?

   YES 

   Perform the trouble diagnosis for ignition power supply circuit. Refer to WIRING DIAGRAM - IGNITION POWER SUPPLY - .

   NO 

   Repair or replace malfunctioning component.

4. CHECK EPS CONTROL UNIT POWER SUPPLY CIRCUIT (3)
   
   
   1. Turn ignition switch OFF.
   2. Check voltage between EPS control unit harness connector terminal and ground.

      EPS control unit		-	Voltage (Approx.)
      Connector	Terminal
      E23	17	Ground	Battery voltage

   3. Turn ignition switch ON.
      CAUTION:

      Never start the engine.

   4. Check voltage between EPS control unit harness connector and ground.

      EPS control unit		-	Voltage (Approx.)
      Connector	Terminal
      E23	17	Ground	Battery voltage

   Is the inspection result normal?

   YES 

   GO TO STEP 6  .

   NO 

   GO TO STEP 5  .

5. CHECK EPS CONTROL UNIT POWER SUPPLY CIRCUIT (4)
   
   
   1. Turn ignition switch OFF.
   2. Check the 60A fusible link (J).
   3. Check the harness for open or short between EPS control unit harness connector E23 terminal 17 and the 60A fusible link (J).

   Is the inspection result normal?

   YES 

   Perform the trouble diagnosis for power supply circuit. Refer to WIRING DIAGRAM - BATTERY POWER SUPPLY - .

   NO 

   Repair or replace malfunctioning component.

6. CHECK CONNECTOR
   
   
   1. Turn ignition switch OFF.
   2. Disconnect torque sensor harness connector.
   3. Check terminal for deformation, disconnection, looseness, and so on. If any malfunction is found, repair or replace terminal.

   Is the inspection result normal?

   YES 

   Replace EPS control unit. Refer to REMOVAL AND INSTALLATION .

   NO 

   Repair or replace malfunctioning component.