Code No. C2251: Tension sensor malfunction
caution |
- 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
).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When you replace the electric parking brake actuator, use the M.U.T.-III to initialise learnt value for the actuator (Refer to
).
- If you fail to initialise learnt value, the tension sensor initialised tension value, which the electric parking brake ECU stores, deviates from the actual value. This may cause diagnosis code C2251 to be set although the system functions normally.
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OPERATION
The electric parking brake ECU monitors how the parking brake cable is tensioned by using the tension sensor, which is incorporated in the electric parking brake actuator.
DIAGNOSIS CODE SET CONDITIONS
If the tension sensor fails, the diagnosis code will be set.
PROBABLE CAUSES
- Parking brake cable(s) seized or dragged
- Parking brake lining improperly adjusted (excessive clearance) or worn
- Tension sensor in the electric parking brake actuator fails
- Wires or connector(s) for the electric parking brake actuator fail
- Malfunction of the electric parking brake ECU
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STEP 1. Parking brake cable check
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Check the parking brake rear cables for proper installation, seizure or dragging.
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Q.
Is the check result normal?
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Go to Step 2.
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Repair or replace the parking brake rear cable.
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STEP 2. Parking brake lining check
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Check the shoe and lining assembly (LH, RH) for proper installation and thickness, and adjust the clearance if necessary.
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Q.
Is the check result normal?
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Go to Step 3.
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Adjust or replace the shoe and lining assembly.
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STEP 3. M.U.T.-III data list
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(1)Check the following data list (Refer to ).
- Item No.40: Tension sensor output fail
- Item No.41: Tension sensor power fail
- Item No.42: Tension sensor compare fail
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(2)Check the data list, and take a note which item is marked as "Fail".
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(3)Erase the diagnosis code.
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(4)Turn the ignition switch to the LOCK (OFF) position.
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(5)Turn the ignition switch to the ON position.
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(6)Place the selector lever to the "P" position, depress the brake pedal and then operate the electric parking brake switch.
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(7)Check the data list again as described in step (1). OK: All items are marked as "Normal"
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Q.
Is the check result normal?
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Go to Step 4.
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Replace the electric parking brake actuator (Refer to ).
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STEP 4. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to the LOCK (OFF) position.
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(3)Turn the ignition switch to the ON position.
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(4)Check if the diagnosis code is set.
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Q.
Is diagnosis code No. C2251 set?
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Replace the electric parking brake ECU (Refer to ).
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
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