Toyota Avalon (XX50): NE Signal Circuit (C1224). SA1 Solenoid Circuit (C1225-C1228,C1468,C1469,C146A,C146B). Steering Angle Sensor Circuit (C1231)

NE Signal Circuit (C1224)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives engine speed signals from the ECM via CAN communication.

PROCEDURE

(a) Check if CAN communication system DTCs are output.

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B

INSPECT CAN COMMUNICATION SYSTEM

A

(a) Check if SFI system DTCs are output.

A

REPLACE ECM

B

INSPECT SFI SYSTEM

SA1 Solenoid Circuit (C1225-C1228,C1468,C1469,C146A,C146B)

DESCRIPTION

These solenoids turn on when signals are received from the skid control ECU (brake actuator assembly) and they control the pressure acting on the wheel cylinders to control the braking force.

WIRING DIAGRAM

Refer to DTC C146E.

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CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration.

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PROCEDURE

HINT:

These codes are detected when a problem is determined in the skid control ECU (brake actuator assembly).

The solenoid circuits are in the skid control ECU (brake actuator assembly).

Therefore, solenoid circuit inspection and solenoid unit inspection cannot be performed. Be sure to check if any DTCs are output before replacing the skid control ECU (brake actuator assembly).

(a) Clear the DTCs.

(b) Turn the engine switch off.

(c) Start the engine.

(d) Drive the vehicle at a speed of 20 km/h (12 mph) or more.

(e) Check if the same DTC is output.

HINT:

• The skid control ECU (brake actuator assembly) performs self diagnosis of the solenoid circuit after the engine switch is turned on (IG).
• If the normal system code is output (no DTCs are output), slightly jiggle the connectors, wire harness, and fuses of the skid control ECU (brake actuator assembly).
• If any DTCs are output while jiggling a connector or wire harness of the skid control ECU (brake actuator assembly), inspect and repair the connector or wire harness.
• If no DTCs were output when reconfirming DTCs, checking for intermittent problems is necessary because it is suspected that the original DTCs were stored due to the poor connection of a connector terminal.

A

USE SIMULATION METHOD TO CHECK

B

REPLACE BRAKE ACTUATOR ASSEMBLY

Steering Angle Sensor Circuit (C1231)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives steering angle sensor signals via CAN communication. When a malfunction occurs in the communication line with the steering angle sensor, DTC U0126 (Lost Communication With Steering Angle Sensor Module) is stored.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

• When U0126 is output together with C1231, inspect and repair the trouble areas indicated by U0126 first.

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• When a speed sensor or yaw rate and acceleration sensor (airbag sensor assembly) is malfunctioning, DTCs for the steering angle sensor may be output even when the steering angle sensor is normal. When DTCs for a speed sensor or the yaw rate and acceleration sensor (airbag sensor assembly) are output together with DTCs for the steering angle sensor, inspect and repair the speed sensor and yaw rate and acceleration sensor (airbag sensor assembly) first, and then inspect and repair the steering angle sensor.

PROCEDURE

(a) Clear the DTCs.

(b) Turn the engine switch off.

(c) Turn the engine switch on (IG) again and check that no CAN communication system DTCs are output.

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(d) Drive the vehicle at a speed of 35 km/h (22 mph), turn the steering wheel to the right and left, and check that no speed sensor and/or yaw rate and acceleration sensor DTCs are output.

HINT:

• When CAN communication system DTCs are output, repair the CAN communication system before repairing each corresponding sensor.
• If there is a malfunction in a speed sensor or the yaw rate and acceleration sensor (airbag sensor assembly), an abnormal value may be output even though the steering angle sensor is normal.
• If speed sensor and yaw rate and acceleration sensor DTCs are output simultaneously, repair the sensors and inspect the steering angle sensor.

B

INSPECT CAN COMMUNICATION SYSTEM

C

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

D

USE SIMULATION METHOD TO CHECK

A

(a) Turn the engine switch off.

*a Front view of wire harness connector (to Steering Angle Sensor)

(b) Remove the steering wheel and column cover.

(c) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(d) Disconnect the G48 steering angle sensor connector.

(e) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Voltage:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

OK

(a) Turn the engine switch off.

*a Front view of wire harness connector (to Steering Angle Sensor)

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

NOTICE:

Before measuring the resistance of the steering angle sensor, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or switches, or opening or closing the doors.

Standard Resistance:

OK

REPLACE STEERING ANGLE SENSOR

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)