POWER STEERING SYSTEM FAIL-SAFE CHART

If a problem occurs in the power steering system, the EPS warning light comes on in the combination meter and the power steering assist is stopped, locked at a particular point, or decreased simultaneously to protect the system.

Table 1. Power Steering System
DTC Code	Detection Condition	Fail-safe Operation
C1511	Torque sensor malfunction	Power assist stops.
C1512
C1513
C1514
C1521	Motor circuit malfunction
C1524	Motor circuit malfunction
C1528	Motor rotation angle sensor malfunction
C1531	ECU malfunction
C1532
C1533		Power assist continues as normal.
C1534		Assist force is restricted.
C1541	Skid control malfunction	The amount of power assist is locked at the 140 km/h (87 mph) level of power assist.
C1551	IG power supply voltage error	Power assist continues as normal.
C1552	PIG power supply voltage error	Power assist continues as normal.
C1554	Power supply relay malfunction	Power assist stops.
C1555	Motor relay malfunction	Power assist stops.
C1581	Assist map not written in power steering ECU	Control is performed using the default settings.
C1582	Assist map mismatch in power steering ECU	Control is performed using the current assist map.
U0100	ECM communication error	Power assist continues as normal*1.
U0100	ECM communication error	Power assist stops*2.
U0129	Skid control ECU communication error	The amount of power assist is locked at the 140 km/h (87 mph) level of power assist.

Tip:

*1: When the DTC is stored while the engine is running.
*2: When the DTC is stored before the engine is started.
The amount of power assist may be decreased to prevent the motor and ECUs from overheating if the steering wheel is continuously turned when the vehicle is either stopped or driven at a low speed, or if the steering wheel is kept at either full lock position for a long time. In such cases, the amount of power assist returns to normal if the steering wheel is not turned for approximately 10 minutes with the engine idling.
If the battery is not sufficiently charged or the voltage decreases temporarily, the amount of power assist is reduced and the EPS warning light comes on. In such cases, the amount of power assist returns normal when the battery voltage recovers.