Code No.C1225:
Deviation between wheel speed (Abnormality in tyre size)
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- If there is any
problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis,
diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table
 ).
- Before replacing the ECU, ensure that the communication circuit is normal.
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OPERATION
- The wheel speed sensor is a kind of a pulse generator.
It consists of encoders (a plate on which north and south pole sides of the magnets are arranged
alternately) for detecting the wheel speed which rotates at the same speed of the wheels and
wheel speed sensors. This sensor outputs frequency pulse signals in proportion to the wheel
speed.
- The pulse signals, which the wheel speed sensor creates, are sent to ABS-ECU. ABS-ECU
uses the frequency of the pulse signals to determine the wheel speed.
DIAGNOSIS CODE SET CONDITION
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 30 km/h.
PROBABLE CAUSES
- Installation of different size tyres
- Wheel speed sensor malfunction
- ABS-ECU malfunction
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STEP 1. M.U.T.-III CAN bus diagnosis
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Use M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 3.
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 Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
On completion, go to Step 2.
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STEP 2. Diagnosis code recheck after resetting CAN bus lines
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(1)Drive the vehicle at 30 km/h or more.
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(2)Turn the ignition switch from the "ON" position to the "LOCK" (OFF) position.
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Q.
Is diagnosis code No.C1225 set?
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Go to Step 3.
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This diagnosis is complete.
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STEP 3. Check the installation condition of the wheel and tyres.
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Q.
Is the check result normal?
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Go to Step 4.
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Install the correct size tyres. Then go to Step 6.
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STEP 4. Check for wheel speed sensor as a single unit
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Refer to .
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the wheel speed sensor (Refer to ). Then
go to Step 6.
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STEP 5. Check whether the diagnosis code is set again.
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(1)Drive the vehicle at 30 km/h or more.
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(2)Turn the ignition switch from the "ON" position to the "LOCK" (OFF) position.
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Q.
Is diagnosis code No.C1225 set?
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Replace the hydraulic unit [(integrated with ABS-ECU) Refer to ].
Then go to Step 6.
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunctions ).
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STEP 6. Check whether the diagnosis code is set again.
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(1)Drive the vehicle at 30 km/h or more.
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(2)Turn the ignition switch from the "ON" position to the "LOCK" (OFF) position.
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Q.
Is diagnosis code No.C1225 set?
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Return to Step 1.
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The procedure is complete.
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