EPS Warning Light Circuit

POWER ASSIST SYSTEMS: POWER STEERING SYSTEM: EPS Warning Light Circuit; 2013 MY FR-S [03/2012 -]
- EPS Warning Light Circuit

DESCRIPTION

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

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* If the power steering ECU assembly is replaced with a new one, perform rotation angle sensor initialization and torque sensor zero point calibration Programming and Relearning.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT
When the power supply voltage to the power steering ECU assembly (terminals IG and PIG) drops, required steering effort increases and the EPS warning light turns on.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR

(a) Turn the ignition switch to ON.

(b) 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 -- Continue to next step.

2. CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

(a) Check for DTCs Diagnosis System.

OK:

DTC is not output.

NG -- GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) How to Proceed With Troubleshooting
OK -- Continue to next step.

3. READ VALUE USING TECHSTREAM (IG POWER SUPPLY)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / EMPS / Data List.

EMPS

OK:

The normal condition value is displayed the Techstream.

NG -- CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BATTERY/BODY GROUND)
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (PIG POWER SUPPLY)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Start the engine.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / EMPS / Data List.

EMPS

OK:

The normal condition value is displayed the Techstream.

NG -- CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BATTERY/BODY GROUND)
OK -- Continue to next step.

5. PERFORM ACTIVE TEST USING TECHSTREAM (METER / GAUGE SYSTEM)

(a) Perform the Active Test of the combination meter using the Techstream Meter / Gauge System.

Combination Meter

(b) 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 -- REPLACE COMBINATION METER ASSEMBLY Removal

OK -- REPLACE POWER STEERING ECU ASSEMBLY Removal

6. CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - BATTERY/BODY GROUND)

(a) Disconnect the A14 and A15 power steering ECU assembly connectors.

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

Standard Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE POWER STEERING ECU ASSEMBLY Removal

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

(a) Disconnect the A14 power steering ECU assembly connector.

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

Standard Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE POWER STEERING ECU ASSEMBLY Removal