EPS Warning Light Circuit: Procedure

1. Turn the ignition switch to ON.
2. Check the indication condition of the EPS warning light by wiggling the power steering ECU assembly connector and wire harness up and down, and right and left.

   OK

   EPS warning light indication condition does not change.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Check for DTCs. Refer to DIAGNOSIS SYSTEM [07/2013 - 12/2013] .

   OK

   DTC is not output.

NG → See step   10 

OK: Go to next step 

1. Turn the ignition switch off.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Turn the Techstream on.
5. Enter the following menus: Chassis / EMPS / Data List.
   EMPS
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   IG Power Supply	ECU power source voltage/ Min.: 0.0000 V Max.: 20.1531 V	9 to 16 V	The ignition switch is ON.

   OK

   The normal condition value is displayed the Techstream.

NG → See step   6 

OK: Go to next step 

1. Turn the ignition switch off.
2. Connect the Techstream to the DLC3.
3. Start the engine.
4. Turn the Techstream on.
5. Enter the following menus: Chassis / EMPS / Data List.
   EMPS
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   PIG Power Supply	Power source voltage to active motor/ Min.: 0.0000 V Max.: 20.1531 V	9 to 16 V	The engine is running and power steering is operating.

   OK

   The normal condition value is displayed the Techstream.

NG → See step   7 

OK: Go to next step 

1. Perform the Active Test of the combination meter using the Techstream. Refer to DATA LIST / ACTIVE TEST [07/2013 - 12/2013] .
   COMBINATION METER
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Indicat. EPS	EPS warning light	OFF/ON	Vehicle is stopped and engine is idling

2. Check that the EPS warning light operates in accordance with the Active Test.

   HINT: 

   Reconnect the connectors and restore the vehicle to its previous condition before checking the combination meter.

NG → See step   8 

OK → See step   9 

1. Disconnect the A14 and A15 power steering ECU assembly connectors.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A15-6 (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
   A14-2 (PGND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9 

1. Disconnect the A14 power steering ECU 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
   A14-1 (PIG) - Body ground	Always	9 to 16 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A14-2 (PGND) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9