POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model): Heavy Steering Feel (EPS Warning Light (Yellow)); 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM1000000028H02
Model Year Start: 2023	Model: GR Corolla	Prod Date Range: [11/2022 - ]
Title: POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model): Heavy Steering Feel (EPS Warning Light (Yellow)); 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 - ]

Heavy Steering Feel (EPS Warning Light (Yellow))

PROCEDURE

1.	READ VALUE USING GTS

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

(b) Read the Data List according to the display on the GTS.

Chassis > EMPS > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Battery Voltage Drop History	Number of times vehicle auxiliary battery voltage dropped	Min.: 0 Max.: 255	-	-
Engine Revolution Ready Signal Communication Failure History	Vehicle speed input value sent via CAN (equal to value indicated on speedometer)	Min.: 0 Max.: 255	-	-
Steering Angle Sensor Signal Communication Failure History	Number of times steering angle sensor signal was interrupted	Min.: 0 Max.: 255	-	-
Vehicle Speed Signal Invalid History	Number of times steering angle sensor signal was interrupted	Min.: 0 Max.: 255	-	-
Overheat Prevention Control History	Number of times assist limit performed due to estimated temperature of power steering ECU and motor coil	Min.: 0 Max.: 255	-	-
Power Supply Voltage Drop Control History	Number of times assist limit performed due to battery voltage having dropped to 9 V or less	Min.: 0 Max.: 255	-	-
Power Supply Voltage Drop Restraint Control History	Number of times assist limit performed due to battery voltage having dropped to 9.7 V or less	Min.: 0 Max.: 255	-	-
Engine Stall/READY OFF Control History	Number of times assist limit performed due to engine stall	Min.: 0 Max.: 255	-	-
High Load Continuous Control Number of Times	Number of times assist limit performed to prevent motor from overheating when overloaded due to steering wheel being turned to full lock position for an extended period of time, tire pressing against curbstone, etc.	Min.: 0 Max.: 255	-	-
Vehicle Speed Signal Fault Control History	Number of times assist power set to a value suitable for high-speed driving when driving at high speeds due to an abnormal vehicle speed signal	Min.: 0 Max.: 255	-	-
Load Control History	Number of times electric load limited to ensure stable vehicle power when power steering could not function appropriately or battery voltage was too low to ensure stable power steering	Min.: 0 Max.: 255	-	-

Chassis > EMPS > Data List

Tester Display
Battery Voltage Drop History
Engine Revolution Ready Signal Communication Failure History
Steering Angle Sensor Signal Communication Failure History
Vehicle Speed Signal Invalid History
Overheat Prevention Control History
Power Supply Voltage Drop Control History
Power Supply Voltage Drop Restraint Control History
Engine Stall/READY OFF Control History
High Load Continuous Control Number of Times
Vehicle Speed Signal Fault Control History
Load Control History

HINT:

If the auxiliary battery is not sufficiently charged or the voltage decreases temporarily, the amount of power assist will be reduced and the EPS warning light will come on. In such cases, the amount of power assist returns to normal when the auxiliary battery voltage recovers.

OK:

No control history

USE SIMULATION METHOD TO CHECK

2.	CHECK FOR VEHICLE CONTROL HISTORY (POWER STEERING SYSTEM)

(a) Check for vehicle control history and note any codes that are output.

Chassis > EMPS > Utility

Tester Display
Vehicle Control History (RoB)

(1) Record the vehicle control history.

Result	Proceed to
Vehicle control history is not output	A
Vehicle control history other than [X206D] are output	B
Vehicle control history [X206D] is output	C

USE SIMULATION METHOD TO CHECK

GO TO VEHICLE CONTROL HISTORY

3.	CHECK FOR VEHICLE CONTROL HISTORY FREEZE FRAME DATA (POWER STEERING SYSTEM)

(a) Check for vehicle control history freeze frame data and note any codes that are output.

Chassis > EMPS > Utility

Tester Display
Vehicle Control History (RoB)

(1) Record the vehicle control history.

Result	Proceed to
Vehicle control history is not output	A
Vehicle control history freeze frame data [Status of Vehicle Power (IGP PDC) is OFF] and [Status of Vehicle Power (IGR PDC) is OFF] are output	B
Vehicle control history freeze frame data [Status of Vehicle Power (IGP PDC) is OFF] and [Status of Vehicle Power (IGR PDC) is ON] are output	C

GO TO CAN COMMUNICATION SYSTEM

GO TO PROBLEM SYMPTOMS TABLE (ENGINE STALLS)

for G16E-GTS: Click here

for M20A-FKS: Click here

4.	CHECK VEHICLE CONTROL HISTORY (AIRBAG SYSTEM)

(a) Check for vehicle control history freeze frame data and note any codes that are output.

Body Electrical > SRS Airbag > Utility

Tester Display
Vehicle Control History (RoB)

Record Data Item Chart

Tester Display	Measurement Item	Range	Diagnostic Note
Vehicle Speed	Vehicle speed at main driven wheels	0 to 200 km/h	If the vehicle speed is 200 km/h or more, "200 km/h" is displayed.
Engine RPM Data	Number of crankshaft revolutions in 1 minute	0 to 12800 rpm	-
Shift Position Signal	Shift lever position	N / D / R / P / 5 / 4 / 3 / 2 / LO / B / SD / S-Mode / Undetermined	-

(1) Record the vehicle control history.

HINT:

If the engine is stopped while the vehicle is stationary and the shift position is not P, the EPS warning light (yellow) illuminates and the message "Engine Stopped Steering Power Low" will be displayed on the multi-information display in the combination meter assembly, but this is caused by incorrect operation and is not a malfunction.

Result	Proceed to
Vehicle control history (vehicle speed 0 km/h or more, engine speed 0 rpm and shift position not in P) is output	A
Vehicle control history (vehicle speed 0 km/h or more, engine speed 0 rpm and shift position not in P) is not output	B

INCORRECT OPERATION

If incorrect operation of the engine switch causes unintended IG OFF operation while the shift position is not P, the engine will stop thus causing EPS shutdown and illumination of the EPS warning light (yellow), but this is not a malfunction. (EPS control during engine stall)

USE SIMULATION METHOD TO CHECK