Inspection Procedure

HINT:

When the power source voltage to the power steering ECU (terminals IG and PIG) drops, required steering effort increases and the P/S warning light turns on.

1. CHECK FOR DTC 
   1. Using the Techstream, check for DTCs and confirm that there are no problems in the CAN communication system.

      OK: CAN DTCs are not output. 

      NG: GO TO CAN COMMUNICATION SYSTEM 

      OK: Go to Next Step 

2. READ VALUE USING TECHSTREAM (IG POWER SUPPLY) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the Techstream on.
   4. Check the IG power source voltage. Enter the following menus: Chassis/EMPS/Data List.

      EMPS 

      DATA LIST REFERENCE
      
      

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      IG Power Supply	ECU power source voltage: Min.: 0 V Max.: 20.1531 V	11 to 14 V	Ignition switch ON

      OK: Go to step  5

      NG: Go to Next Step 

3. INSPECT FUSE (ECU-IG1) 
   1. Remove the ECU-IG1 fuse from the instrument panel junction block.
   2. Measure the resistance of the fuse.

      OK: Below 1 Ω 

      NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

      OK: Go to Next Step 

4. CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU) 
   1. Disconnect the A1 and E18 power steering ECU connectors.
   2. Measure the voltage of the wire harness side connectors.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      E18-5 (IG) - A1-2 (PGND)	Ignition switch ON	11 to 14 V

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      Fig 1: Identifying Terminals Of A1 And E18 Power Steering ECU Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: Go to Next Step 

5. READ VALUE USING TECHSTREAM (PIG POWER SUPPLY) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the Techstream on.
   4. Check the IG power source voltage. Enter the following menus: Chassis/EMPS/Data List.

      EMPS 

      DATA LIST REFERENCE
      
      

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      PIG Power Supply	PIG power source voltage: Min.: 0 V Max.: 20.1531 V	11 to 14 V	Power steering in operation

      OK: Go to step  8

      NG: Go to Next Step 

6. INSPECT FUSE (EMPS) 
   1. Remove the EMPS fuse from the engine room No. 1 relay block.
   2. Measure the resistance of the fuse.

      OK: Below 1 Ω 

      NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

      OK: Go to Next Step 

7. CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU AND BODY GROUND) 
   1. Disconnect the A1 power steering ECU connector.
   2. Measure the voltage of the wire harness side connector.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      A1-1 (PIG) - A1-2 (PGND)	Ignition switch ON	11 to 14 V

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      Fig 2: Identifying Terminals Of A1 Power Steering ECU Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: Go to Next Step 

8. PERFORM ACTIVE TEST USING TECHSTREAM 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Body Electrical/Combination Meter/Active Test.

      Combination Meter 

      ACTIVE TEST REFERENCE
      
      

      Tester Display	Test Part	Control Range	Diagnostic Note
      Indicat. EPS	P/S indicator	Indicator ON or OFF	Confirm that the vehicle is stopped, engine idling

      OK: Indicator comes on. 

      NG: REPLACE COMBINATION METER ASSEMBLY 

      OK: REPLACE POWER STEERING ECU