Toyota Yaris: Power Steering System / Supply Voltage Circuit Circuit Voltage Above Threshold (C123A17)

Toyota Yaris XP210 (2020-2026) Reapir and Service Manual / Steering / Power Assist Systems / Power Steering System / Supply Voltage Circuit Circuit Voltage Above Threshold (C123A17)

DESCRIPTION

The power steering ECU assembly distinguishes the ignition switch status as ON or off through the IG power source circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Return-to-normal Condition	Note
C123A17	Supply Voltage Circuit Circuit Voltage Above Threshold	IG voltage is 18.5 V or more	EPS-IGR fuse IG power source circuit Power steering ECU assembly	EPS warning light: Comes on	The ECU judges the system has returned to normal or the ignition switch is turned ON again	-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When the power steering ECU assembly has been replaced, perform Power Steering ECU Initial Setting (assist map writing).

Click here

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (IG POWER SOURCE)

(a) Disconnect the H1 power steering ECU assembly connectors.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
H1-1 (IG) - Body ground	Ignition switch ON	8 to 16 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK HARNESS AND CONNECTOR (IG POWER SOURCE)

(a) Disconnect the H2 power steering ECU assembly connectors.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
H2-2 (PGND) - Body ground	Always	Below 1 Ω

REPLACE POWER STEERING ECU ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

Power Steering Control Module Processor System Internal Failure (C05D604,...,C15D362)

DESCRIPTION DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Return-to-normal Condition Note C05D604 Power Steering Control Module Processor System Internal Failure ECU internal malfunction (CPU malfunction) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C05D646 Power Steering Control Module Processor Calibration / Parameter Memory Failure ECU internal malfunction (EEPROM error) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C05D649 Power Steering Control Module Processor Internal Electronic Failure ECU internal malfunction (Peripheral circuit malfunction) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C10001C Control Module Internal Temperature Sensor "A" Circuit Voltage Out of Range ECU temperature sensor "A" range malfunction Power steering ECU assembly EPS warning light: Comes on The ECU judges the system has returned to normal - C152A18 Power Steering Motor "A" Circuit Current Below Threshold Motor "A" low current malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C152A19 Power Steering Motor "A" Circuit Current Above Threshold Motor "A" overcurrent Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C152B18 Power Steering Motor "B" Circuit Current Below Threshold Motor "B" low current malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C152B19 Power Steering Motor "B" Circuit Current Above Threshold Motor "B" overcurrent Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C153A00 Malfunction of Power Steering Motor "A" Inverter Pre-Driver Inverter "A" pre-driver circuit malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C153A19 Power Steering Motor "A" Inverter Circuit Current Above Threshold Inverter "A" short circuit malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C153B00 Malfunction of Power Steering Motor "B" Inverter Pre-Driver Inverter "B" pre-driver circuit malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C153B19 Power Steering Motor "B" Inverter Circuit Current Above Threshold Inverter "B" short circuit malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C154A7E Power Supply & Contrary Connection Protection Relay "A" Actuator Stuck On Contrary connection protection relay "A" short circuit malfunction (initial check) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C154A7F Power Supply & Contrary Connection Protection Relay "A" Actuator Stuck Off Contrary connection protection relay "A" open circuit malfunction (initial check) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C154B7E Power Supply & Contrary Connection Protection Relay "B" Actuator Stuck On Contrary connection protection relay "B" short circuit malfunction (initial check) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C154B7F Power Supply & Contrary Connection Protection Relay "B" Actuator Stuck Off Contrary connection protection relay "B" open circuit malfunction (initial check) Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C157A11 Power Steering Motor "A" Current Sensor Circuit Short to Ground Motor "A" current sensor low voltage malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C157A62 Power Steering Motor "A" Current Sensor Signal Compare Failure Motor "A" current sensor correlation malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C157B11 Power Steering Motor "B" Current Sensor Circuit Short to Ground Motor "B" current sensor low voltage malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C157B62 Power Steering Motor "B" Current Sensor Signal Compare Failure Motor "B" current sensor correlation malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D11C Power Steering Motor Position Sensor "A" Circuit Voltage Out of Range Rotation angle sensor "A" range malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D162 Power Steering Motor Position Sensor "A" Signal Compare Failure Rotation angle sensor "A" correlation malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D21C Power Steering Motor Position Sensor "B" Circuit Voltage Out of Range Rotation angle sensor "B" range malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D262 Power Steering Motor Position Sensor "B" Signal Compare Failure Rotation angle sensor "B" correlation malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D31C Power Steering Motor Position Sensor "C" Circuit Voltage Out of Range Rotation angle sensor "C" range malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - C15D362 Power Steering Motor Position Sensor "C" Signal Compare Failure Rotation angle sensor "C" correlation malfunction Power steering ECU assembly EPS warning light: Comes on Ignition switch ON again - 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