IG Power Source Circuit

DESCRIPTION

The troubleshooting procedure for a situation in which no DTCs are output but the P/S warning light is always on is specified here. The P/S warning light remains on when there is an open in the IG circuit inputting power source voltage to the power steering ECU assembly.

WIRING DIAGRAM

INSPECTION PROCEDURE

1. CHECK HARNESS AND CONNECTOR

1. Check the indication condition of the P/S warning light while by wiggling the power steering ECU assembly connector and wire harness up and down, and then right and left.

   OK:

   P/S warning light indication condition does not change.
   

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2. INSPECT CAN COMMUNICATION SYSTEM

1. Using the intelligent tester, check for DTCs and confirm that there are no problems in the CAN communication system.

   OK:

   DTCs are not output.
   

NG	GO TO CAN COMMUNICATION SYSTEM

OK

3. INSPECT MULTIPLEX COMMUNICATION SYSTEM (BEAN)

1. Using the intelligent tester, check for DTCs and confirm that there are no problems in the multiplex communication system (BEAN).

   OK:

   DTCs are not output.
   

NG	GO TO MULTIPLEX COMMUNICATION SYSTEM (BEAN)

OK

4. INSPECT FUSE (ECU-IG No.1)

1. Remove the ECU-IG No.1 fuse from the instrument panel J/B LH.

2. Check for continuity of the ECU-IG No.1 fuse.

   OK:

   Continuity
   

NG	REPLACE FUSE

OK

5. INSPECT POWER STEERING ECU ASSEMBLY

1. Disconnect the P43 connector from the power steering ECU assembly.

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

   Voltage:

   Tester connection (Symbols)	Condition	Specified condition
   P43-9 (IG) -P43-5 (PGND)	Ignition switch on	10 to 14 V

OK	Go to step 7

NG

6. CHECK HARNESS AND CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND BODY GROUND)

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

   Resistance:

   Tester connection (Symbols)	Condition	Specified condition
   P43-5 (PGND) - Body ground	Always	Below 1 Ω

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR (BETWEEN POWER STEERING ECU ASSEMBLY AND BATTERY)

7. REPLACE POWER STEERING ECU ASSEMBLY

1. Replace the power steering ECU assembly (Click here).

   NOTICE:

   After replacing the power steering ECU assembly, initialize the rotation angle sensor value and calibrate the torque sensor zero point (Click here).

NEXT

8. CHECK P/S WARNING LIGHT

1. Check the P/S warning light status on the combination meter.

   Standard:

   The P/S warning light is off.
   

OK	END

NG
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE