Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001C0XE
Model Year Start: 2019 Model: GR Corolla Prod Date Range: [06/2018 - 09/2019]
Title: POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model (for Hatchback)): Check Assist Limit Record; 2019 - 2020 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2019]

Check Assist Limit Record

CAUTION / NOTICE / HINT

HINT:

Perform this troubleshooting procedure when no DTCs are output, including DTCs related to CAN communication system malfunctions.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (ASSIST LIMIT RECORD 1)

(a) Using the Techstream, read the Data List item "Assist Limit Record 1".

Click here 2019 - 2020 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2019]; POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model (for Hatchback)): DATA LIST / ACTIVE TEST

Chassis > EMPS > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Assist Limit Record 1

Information of assist limit that was used in the past or is currently in use (latest history)

Unrec, Mtr Overheat, Pow Vol Low, Pow Vol Low Prevent, Eng Stall, Ready OFF, Mtr Overload, DC-DC Malf, Vhcl Spd Sig Malf, Batt Vol Keep

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HINT:

For the Data List item "Assist Limit Record 1", each item in the Range is described below.

 

Range

Description

Diagnostic Note

Assist Limit Record 1

Unrec

No assist limit. Continue with troubleshooting for "Heavy steering".

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Mtr Overheat

When the vehicle is stopped or traveling at low speed, and steering operations are performed repeatedly or the steering wheel is turned all the way to the side and held there for a long time, assist may be limited in order to prevent overheating of the power steering ECU with motor assembly.

After 10 minutes elapse with the engine running and no steering operations being performed, the system will return to normal.

After recovering from the overheated condition, assist can be performed as usual.

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Pow Vol Low

When insufficient battery charge, or battery degradation etc. causes the voltage to temporarily decrease, assist may be stopped.

After the battery condition returns to normal, assist can be performed as usual.

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Pow Vol Low Prevent

When insufficient battery charge, or battery degradation etc. causes the voltage to temporarily decrease, assist may be limited.

After the battery condition returns to normal, assist can be performed as usual.

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Eng Stall

When the engine stalls, battery charge becomes insufficient, so assist is stopped.

After recovering from the engine stall, assist can be performed as usual.

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Ready OFF

After Ready ON, if a malfunction in the HV system etc. causes a return to Ready OFF, the HV battery charge becomes insufficient, so assist is stopped.

After returning to Ready ON state, assist can be performed as usual.

Not displayed for this vehicle

Mtr Overload

When the steering wheel cannot turn, such as when a road wheel is against a curb, if the driver continues to apply force to the steering wheel, current to the motor may be limited to prevent overheating.

When the steering wheel is returned to a neutral position, assist can be performed as usual.

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DC-DC Malf

If there is a malfunction in the DC-DC converter, etc., assist may be limited.

After the DC-DC converter returns to normal, assist can be performed as usual.

Not displayed for this vehicle

Vhcl Spd Sig Malf

If the vehicle speed signal is abnormal due to a wheel speed sensor malfunction, etc., assist may be limited.

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Batt Vol Keep

When insufficient battery charge, or battery degradation etc. causes the voltage to temporarily decrease, assist may be limited.

After the battery condition returns to normal, assist can be performed as usual.

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Chassis > EMPS > Data List

Tester Display

Assist Limit Record 1

(b) Based on the "Assist Limit Record 1" information, the following Data List items and the information from the customer interview, explain the situation to the customer.

Chassis > EMPS > Data List

Tester Display

Record 1 Key Cycle

Record 1 Key Cycle Elapsed Time

HINT:

If it is necessary to investigate further into the past, check the "Assist Limit Record 2" and "Assist Limit Record 3" information in the same way as "Assist Limit Record 1".

NEXT

END