EPS Warning Light Circuit: Procedure

1. Check the connection condition of the electric power steering column sub-assembly and power steering ECU assembly connectors.

   OK

   The electric power steering column sub-assembly and power steering ECU assembly connectors are securely connected.

2. Check that the ground wire is securely installed with the bolt. Refer to INSTALLATION [06/2012 - ] - Step 3 .

   OK

   The ground wire is securely installed with the bolt.

NG → See step   11 

OK: Go to next step 

1. Check for DTCs. Refer to DIAGNOSIS SYSTEM [06/2012 - ] .

   OK

   DTCs are not output.

NG → See step   10 

OK: Go to next step 

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream 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 Techstream.
   EMPS
   
   

   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	Engine switch on (IG)

   OK

   The normal condition value is displayed on the Techstream.

NG → See step   4 

OK → See step   9 

1. Disconnect the Hc2 ECU wire sub-assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Hc2-5 (IG) - Body ground	Engine switch on (IG)	8 to 16 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to ECU Wire Sub-assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the c2 power steering ECU assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   c2-2 (PGND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   13 

OK: Go to next step 

1. Disconnect the c1 power steering ECU assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   c1-1 (IG) - Hc2-5 (IG)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Power Steering ECU Assembly)
   *b	Front view of wire harness connector (to Vehicle Wire Harness)

NG → See step   13 

OK: Go to next step 

1. Reconnect the c1 and c2 power steering ECU assembly connectors.
2. Perform the Active Test of the combination meter assembly using the Techstream. Refer to DATA LIST / ACTIVE TEST [06/2012 - ] .
3. Check the combination meter assembly.

   OK

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

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part. Refer to PROBLEM SYMPTOMS TABLE [06/2012 - ] .

NG → See step   8 

OK → See step   12