Code No. C1274: Motor Relay (Stuck On)




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


The ASTC-ECU contains the power supply circuit (terminal 15) for the motor. ACTS-ECU incorporates a monitor to check if power is supplied to the motor for running.

DIAGNOSIS CODE SET CONDITIONS


This code is set when the power supply and motor relay are normal but the motor does not run even if the motor relay is turned ON.

PROBABLE CAUSES


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

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)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1274 set?

Go to Step 3.

The procedure is complete.

STEP 3. Check the ABS motor relay connector A-49X for loose, corroded or damaged terminals, or terminals pushed back in the connector.


Q. Is the check result normal?

Go to Step 4.

Repair or replace the damaged component(s). Then go to Step 6.

STEP 4. Check the ABS motor relay.
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the ABS motor relay. Then go to Step 6.

STEP 5. 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)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1274 set?

Replace the hydraulic unit assembly (integrated with ASTC-ECU). Then go to Step 6.

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 6. Check that the ABS warning lamp, brake warning lamp, ASTC indicator lamp and ASTC OFF indicator lamp are turned OFF.
Check that the ABS warning lamp, Brake warning lamp, ASTC indicator lamp and ASTC OFF indicator lamp goes out when the vehicle is driven at 10km/h or more.

Q. Does the ABS warning lamp go out?
Go to Step 7.
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 7. 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)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1274 set?

Go to Step 1.

The procedure is complete.