Power Steering System

POWER STEERING: POWER STEERING SYSTEM: EPS Warning Light Circuit
- EPS Warning Light Circuit

DESCRIPTION

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

WIRING DIAGRAM





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.

PROCEDURE

1. CHECK FOR DTC

(a) 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 -- Continue to next step.

2. READ VALUE USING TECHSTREAM (IG POWER SUPPLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch ON.

(c) Turn the Techstream on.

(d) Check the IG power source voltage. Enter the following menus: Chassis / EMPS / Data List.

EMPS





OK -- READ VALUE USING TECHSTREAM (PIG POWER SUPPLY)
NG -- Continue to next step.

3. INSPECT FUSE (ECU-IG1)

(a) Remove the ECU-IG1 fuse from the instrument panel junction block.

(b) Measure the resistance of the fuse.

OK:

Below 1 Ohms

NG -- CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE
OK -- Continue to next step.

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

(a) Disconnect the A1 and E18 power steering ECU connectors.





(b) Measure the voltage of the wire harness side connectors.

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. READ VALUE USING TECHSTREAM (PIG POWER SUPPLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch ON.

(c) Turn the Techstream on.

(d) Check the IG power source voltage. Enter the following menus: Chassis / EMPS / Data List.

EMPS





OK -- PERFORM ACTIVE TEST USING TECHSTREAM
NG -- Continue to next step.

6. INSPECT FUSE (EMPS)

(a) Remove the EMPS fuse from the engine room No. 1 relay block.

(b) Measure the resistance of the fuse.

OK:

Below 1 Ohms

NG -- CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (BATTERY - POWER STEERING ECU AND BODY GROUND)

(a) Disconnect the A1 power steering ECU connector.





(b) Measure the voltage of the wire harness side connector.

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

8. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Active Test.

Combination Meter





OK:

Indicator comes on.

NG -- REPLACE COMBINATION METER ASSEMBLY

OK -- REPLACE POWER STEERING ECU