POWER STEERING SYSTEM EPS Warning Light Circuit

DESCRIPTION

If the power steering ECU assembly detects a malfunction, the EPS warning light comes on. At this time, the power steering ECU assembly stores a DTC in its memory.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK CONNECTOR CONNECTION CONDITION

   
   

   1. Jiggle the power steering ECU assembly connectors and wire harness up and down, and left and right to check the illumination condition of the EPS warning light in the combination meter assembly.

      OK
      The EPS warning light illumination condition does not change.

      Tech Tips

      When the EPS warning light is operating properly, it comes on when the ignition switch is turned to ON and goes off when the engine is started.

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. CHECK CAN COMMUNICATION SYSTEM

   
   

   1. Check for DTCs.

      Click here

      OK
      DTCs are not output.

      Result
      Proceed to OK NG

   
   

   NG

   GO TO CAN COMMUNICATION SYSTEM Click here

   OK

3. READ VALUE USING GTS

   
   

   1. Turn the ignition switch off.

   2. Connect the GTS to the DLC3.

   3. Turn the ignition switch to ON.

   4. Turn the GTS on.

   5. Enter the following menus: Chassis / EMPS / Data List.

   6. Select the item "IG Power Supply" in the Data List and read the value displayed on the GTS.

      
      Chassis > EMPS > Data List

      Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
      IG Power Supply	IG power source voltage	Min.: 0.0000 V Max.: 20.1531 V	8 to 16 V	Ignition switch ON

      
      Chassis > EMPS > Data List

      Tester Display
      IG Power Supply

      OK
      The normal condition value is displayed on the GTS.

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU ASSEMBLY) Click here

   OK

4. INSPECT COMBINATION METER ASSEMBLY

   
   

   1. Perform the Active Test of the combination meter assembly using the GTS.

      
      Body Electrical > Combination Meter > Active Test

      Tester Display
      Indicat. EPS

   2. Check the combination meter assembly.

      OK
      The EPS warning light turns on or off in accordance with the GTS operation.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE POWER STEERING ECU ASSEMBLY Click here

   NG

   GO TO METER / GAUGE SYSTEM Click here

5. CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU ASSEMBLY)

   
   

   1. Disconnect the E30 and A53 power steering ECU assembly connectors.

      

      *a

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

      -

      -

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

      Standard Voltage
      Tester Connection Condition Specified Condition E30-1(IG) - Body ground Ignition switch ON 9 to 16 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition A53-1 (PGND) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. INSPECT COMBINATION METER ASSEMBLY

   
   

   1. Reconnect the E30 and A53 power steering ECU assembly connectors.

   2. Perform the Active Test of the combination meter assembly using the GTS.

      
      Body Electrical > Combination Meter > Active Test

      Tester Display
      Indicat. EPS

   3. Check the combination meter assembly.

      OK
      The EPS warning light turns on or off in accordance with the GTS operation.

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE POWER STEERING ECU ASSEMBLY Click here

   NG

   GO TO METER / GAUGE SYSTEM Click here