Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: EPS Warning Light Circuit

1.

CHECK ASSIST LIMIT RECORD

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, Vhcl Spd Sig Malf, Batt Vol Keep

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Assist Limit Record 1

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 motor assembly and power steering ECU assembly.

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

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

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.

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.

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.

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.

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.

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.

Vhcl Spd Sig Malf

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

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.

Record 1 Key Cycle

Number of times that the engine switch was turned on (IG) before Assist Limit Record 1 was stored

Min.: 0 times

Max.: 65535 times

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Record 1 Key Cycle Elapsed Time

Period of time that elapsed since the engine switch was turned on (IG) before Assist Limit Record 1 was stored

Min.: 0.0 s

Max.: 53687091.1 s

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Record 1 Key Cycle

Record 1 Key Cycle Elapsed Time

"Unrec" is displayed

A

Other than Unrec is displayed

B

EXPLAIN THE CHECKED "ASSIST LIMIT RECORD 1" TO THE CUSTOMER, CROSS-CHECKING THE DATA LIST ITEMS WITH THE INFORMATION FROM THE CUSTOMER INTERVIEW.

2.

CHECK HARNESS AND CONNECTOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

CHECK CAN COMMUNICATION SYSTEM

CAN communication system DTCs are not output.

A

CAN communication system DTCs are output.

B

GO TO CAN COMMUNICATION SYSTEM

4.

CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - GROUND)

*a

Front view of wire harness connector

(to Power Steering ECU Assembly)

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J4-1 (IG) - Body ground

Engine switch on (IG)

8 to 16 V

J5-1 (PIG) - Body ground

Engine switch on (IG)

9 to 16 V

J5-2 (PGND) - Body ground

Always

Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

INSPECT COMBINATION METER ASSEMBLY

Indicat. EPS

REPLACE POWER STEERING ECU ASSEMBLY

GO TO METER / GAUGE SYSTEM