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Power Steering System (Diagnostic Codes & Circuit Tests): Overview Scion FR-S I

Electronic Steering 6 illustrations ~482 words

DESCRIPTION

The torque sensor converts the rotation torque input to the steering wheel into an electrical signal and sends it to the power steering ECU assembly. Based on this signal, the ECU detects steering effort.

DTC CodeDTC Detection ConditionTrouble Area
C1511A torque sensor (TRQ1) signal error or stopSteering column assembly (torque sensor) Power steering ECU assembly
C1512A torque sensor (TRQ2) signal error or stop
C1513The deviation between torque sensor TRQ1 and TRQ2 exceeds a specified value.
C1514A torque sensor power supply voltage error
C1517Temporary control due to a malfunction related to the torque sensor continues for long time.

Scheme 5

Scheme 5: WIRING DIAGRAM

These DTCs do not indicate a malfunction. The power steering ECU assembly stores these DTCs when it determines that the rotation angle sensor value initialization and torque sensor zero point calibration have not been performed.

DTC CodeDTC Detection ConditionTrouble Area
C1515Torque sensor zero point calibration has not been performed.There is no malfunction if this DTC is not output again after performing torque sensor zero point calibration.
C1525Rotation angle sensor value initialization has not been performed.There is no malfunction if this DTC is not output again after performing rotation angle sensor value initialization.

These DTCs do not indicate a malfunction. The power steering ECU assembly stores these DTCs when it determines that the rotation angle sensor value initialization and torque sensor zero point calibration are incomplete.

DTC CodeDTC Detection ConditionTrouble Area
C1516Torque sensor zero point calibration is incomplete due to the steering wheel being touched during calibration.There is no malfunction if this DTC is not output again after clearing the DTC and torque sensor calibration value, and performing zero point calibration.
C1526Rotation angle sensor value initialization is incomplete due to the steering wheel being touched during calibration.There is no malfunction if this DTC is not output again after clearing the DTC and torque sensor calibration value, and performing rotation angle sensor value initialization.

If the power steering ECU assembly stores these DTCs, it will shut off the power supply relay circuit (built into the power steering ECU assembly) and stop power assist. However, power assist continues if DTC C1533 or C1534 is stored.

DTC CodeDTC Detection ConditionTrouble Area
C1521Motor overcurrentPower steering ECU assembly
C1531An ECU internal malfunction (CPU malfunction)
C1532An ECU internal malfunction (peripheral circuit malfunction)
C1533An ECU internal malfunction (substrate temperature sensor malfunction)
C1534An ECU internal malfunction (EEPROM error)
C1554A power supply relay circuit malfunction

The power steering ECU assembly supplies the current to the power steering motor through the motor circuit.

DTC CodeDTC Detection ConditionTrouble Area
C1522A motor current sensor malfunctionSteering column assembly Power steering ECU assembly
C1523An excessively large current deviation
C1524A short or open in the motor circuit or abnormal voltage or current in the motor circuit
C1555A motor relay malfunction

Scheme 6

Scheme 6: WIRING DIAGRAM

The rotation angle sensor detects the motor rotation angle and sends this information to the power steering ECU assembly.

DTC CodeDTC Detection ConditionTrouble Area
C1528A rotation angle sensor malfunctionRotation angle sensor (built into steering column assembly) Power steering ECU assembly

Scheme 7

Scheme 7: WIRING DIAGRAM

The power steering ECU assembly receives vehicle speed signals from the skid control ECU via CAN communication. The power steering ECU assembly provides appropriate assisting force in accordance with the vehicle speed, based on the signals.

If the power steering ECU assembly stores this DTC, it adjusts the amount of power assist to the amount provided for a speed of 100 km/h (62 mph) and continues the system control.

DTC CodeDTC Detection ConditionTrouble Area
C1541The vehicle speed signals malfunctionSpeed sensor circuit Skid control ECU CAN communication system Power steering ECU assembly

The power steering ECU assembly determines whether the ignition switch status is ON or off through the IG power supply circuit.

DTC CodeDTC Detection ConditionTrouble Area
C1551An IG power supply circuit malfunction inside the ECUECU IG1 fuse IG power supply circuit Power steering ECU assembly

Scheme 8

Scheme 8: WIRING DIAGRAM

When a problem occurs in the power steering system, the power supply relay circuit is shut off to stop the power assist.

DTC CodeDTC Detection ConditionTrouble Area
C1552A PIG power supply circuit malfunction inside the ECUEPS fuse PIG power supply circuit Power steering ECU assembly

Scheme 9

Scheme 9: WIRING DIAGRAM

The power steering ECU assembly stores this DTC when it determines that the assist map is not written in the ECU.

HINT

The assist map is data written in the power steering ECU assembly to control the degree of power assist. The assist map is selected based on the vehicle's specified communication data.

DTC CodeDTC Detection ConditionTrouble Area
C1581The assist map is not written in the power steering ECU assembly.Assist map not written CAN communication system ECM Power steering ECU assembly

If an incorrect power steering ECU assembly or ECM or skid control ECU is installed, DTC C1582 is stored as the vehicle specification and data do not match.

HINT

The assist map is data written in the power steering ECU assembly to control the degree of assistance. The assist map is selected based on the vehicle's specified communication data.

DTC CodeDTC Detection ConditionTrouble Area
C1582Data that does not match the vehicle specification is received through CAN communication.CAN communication system ECM (wrong assembly) Skid control ECU (wrong assembly) Power steering ECU assembly (wrong assembly)

The power steering ECU assembly receives signals from the ECM and skid control ECU (brake actuator assembly) via the CAN communication system.

DTC CodeDTC Detection ConditionTrouble Area
U0100Lost communication with the ECM/PCM "A"CAN communication system ECM
U0122Lost communication with the brake system control moduleCAN communication system Skid control ECU (Brake actuator assembly)
U0416The brake system control module signal malfunction

If the power steering ECU assembly detects a malfunction, the EPS warning light comes on. At this time, the power steering ECU assembly stores a DTC in its memory.

Scheme 10

Scheme 10: WIRING DIAGRAM

See also:
REMOVAL [07/2013 - ]