Code No.C1225: Wheel Speed Sensor Malfunction

caution

If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Diagnose the CAN bus lines before the diagnosis codes (Refer to GROUP 54C, CAN bus-line diagnostic flow

OPERATION

A toothed ABS rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
The amount of voltage generated at each wheel is determined by the clearance between the ABS rotor teeth and the wheel speed sensor, and by the speed of rotation.
The wheel speed sensors transmit the frequency of the voltage pulses and the amount of voltage generated by each pulse to the ABS-ECU.
The hydraulic unit assembly (integrated with ABS-ECU) modulates the amount of braking force individually applied to each wheel cylinder.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set when the average speed of the front wheels differs from that of the rear wheel by 20 % or more after the vehicle speed exceeds 20 km/h.

PROBABLE CAUSES

The most likely causes for these diagnosis codes to set are:

Installation of different size tyres
Damaged wiring harness or connector
Malfunction of the hydraulic unit assembly (integrated with ABS-ECU)

DIAGNOSIS

STEP 1. M.U.T.-III CAN bus diagnostics

caution

Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.

(1)Connect M.U.T.-III to the 16-pin diagnosis connector.
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result normal?

Go to Step 3.

Repair the CAN bus line (Refer to GROUP 54C, CAN bus line Diagnostic flow

). Then go to Step 2.

STEP 2. Check whether the diagnosis code is reset.

caution

Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.

(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Drive the vehicle at 20 km/h or more for 5 seconds or more.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
(5)Turn the ignition switch to the "ON" position.
(6)Check if the diagnosis code is set.
(7)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1225 set?

Go to Step 3.

The procedure is complete.

STEP 3. Check the installation condition of the wheel and tyres.

Refer to GROUP 31, General information

Q. Is the check result normal?

	Go to Step 4.

	Install the correct size tyres. Then go to Step 5.

STEP 4. Check whether the diagnosis code is reset.

Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Drive the vehicle at 20 km/h or more for 5 seconds or more.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
(5)Turn the ignition switch to the "ON" position.
(6)Check if the diagnosis code is reset.
(7)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1225 set?

Replace the hydraulic unit assembly (integrated with ABS-ECU). Then go to Step 5.

It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction

STEP 5. Check whether the diagnosis code is reset.

Q. Is code No.C1225 set?

Repeat the troubleshooting from Step 1.

The procedure is complete.