Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM10000000257FC
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for HV Model): Heavy Steering Feel (EPS Warning Light (Yellow)); 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]

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

OK

USE SIMULATION METHOD TO CHECK

NG

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

A

USE SIMULATION METHOD TO CHECK

B

GO TO VEHICLE CONTROL HISTORY

C

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

A

GO TO CAN COMMUNICATION SYSTEM

B

GO TO PROBLEM SYMPTOMS TABLE (ENGINE STALLS)

C

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

A

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)

B

USE SIMULATION METHOD TO CHECK