POWER STEERING SYSTEM Power Steering Warning Light Circuit

DESCRIPTION

The power steering ECU is connected to the combination meter via CAN communication. If any of the following conditions are detected, the power steering warning light remains on.

• The circuit that supplies power source voltage to the power steering ECU (terminal IG) is open.

• The power supply voltage to the power steering ECU (terminals IG and PIG) drops.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR

   
   

   1. Start the engine.

   2. Check the indication condition of the power steering warning light by wiggling the power steering ECU connector and wire harness up, down, right and left.

      OK
      The power steering warning light indication condition does not change.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. CHECK CAN COMMUNICATION SYSTEM

   
   

   1. Check for DTCs Click here.

      Result

      Result		Proceed to
      DTC is not output		A
      DTC is output	for LHD	B
      	for RHD	C

   
   

   B

   GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

   C

   GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED) Click here

   A

3. CHECK TERMINAL VOLTAGE (IG)

   
   

   1. Disconnect the power steering ECU connector.

   2. 

      Text in Illustration

      *a	Front view of wire harness connector (to Power Steering ECU)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition A29-14 (IG) - Body ground Engine switch on (IG) 11 to 14 V

   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition A29-9 (PGND) - Body ground Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. CHECK EPS RELAY (ELECTRIC POWER STEERING RELAY)

   
   

   1. 

      Remove the EPS relay (electric power steering relay) from the No. 1 engine room relay block.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition 1 - 2 20°C (68°F) 180 to 220 Ω 3 - 5 Battery voltage not applied to terminals 1 and 2 10 kΩ or higher Battery voltage applied to terminals 1 and 2 Below 1 Ω

   
   

   NG

   REPLACE EPS RELAY (ELECTRIC POWER STEERING RELAY)

   OK

5. CHECK TERMINAL VOLTAGE (EPS RELAY)

   
   

   1. Remove the EPS relay (electric power steering relay) from the No. 1 engine room relay block.

      

      Text in Illustration

      *A	for LHD	*B	for RHD
      *a	Component without EPS relay (electric power steering relay) (No. 1 Engine Room Relay Block)	*b	Component without EPS relay (electric power steering relay) (No. 1 Engine Room Relay Block)
      *c	Component without EPS relay (electric power steering relay) EPS Relay (Electric Power Steering Relay) Connection Area	*d	Component without EPS relay (electric power steering relay) EPS Relay (Electric Power Steering Relay) Connection Area

   2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      for LHD
      Tester Connection Condition Specified Condition 2 - Body ground Always 11 to 14 V 5 - Body ground Always 11 to 14 V
      for RHD
      Tester Connection Condition Specified Condition 1 - Body ground Always 11 to 14 V 5 - Body ground Always 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - POWER STEERING ECU)

   
   

   1. Remove the EPS relay (electric power steering relay) from the No. 1 engine room relay block.

   2. Disconnect the A29 power steering ECU connector.

   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition A29-12 (RLY) - 1 Always Below 1 Ω A29-10 (PIG) - 3 Always Below 1 Ω A29-12 (RLY) - A29-10 (PIG) Always 10 kΩ or higher A29-10 (PIG) - Body ground Always 10 kΩ or higher A29-12 (RLY) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition A29-12 (RLY) - 2 Always Below 1 Ω A29-10 (PIG) - 3 Always Below 1 Ω A29-12 (RLY) - A29-10 (PIG) Always 10 kΩ or higher A29-10 (PIG) - Body ground Always 10 kΩ or higher A29-12 (RLY) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. REPLACE POWER STEERING ECU ASSEMBLY

   
   

   1. Replace the power steering ECU assembly Click here.

   2. Perform assist map writing, clear the motor rotation angle sensor calibration value, initialize the motor rotation angle sensor value and calibrate the torque sensor zero point Click here.

   3. Check the illumination condition of the power steering warning light.

      OK
      The power steering warning light illuminates with the engine switch on (IG) and turns off after the engine starts.

   
   

   NG

   REPLACE COMBINATION METER ASSEMBLY Click here

   OK

   END