This code shows in case that a speed signal from any of the 4 wheel speed sensors does not match to the others at any speed.
DTC DETECTING CONDITION
DTC No
Condition
Possible Cause
C1201 (FL)C1204 (FR)C1207 (RL)C1210 (RR)
Speed Jump :
This monitoring is performed for the period that the velocity of each wheel exceeds 2km/h.
-
Controller counts the number of the wheel acceleration of 100g[(25km/h) for 7ms]. When the numbers at one wheel exceed 56 times, or When the numbers at more two wheels exceed 5 times, controller recognize the failure.
-
Controller counts the number of the wheel acceleration of 40g[(10km/h) for 7ms]. When the numbers at one wheel exceed 126 times, or When the numbers at more two wheels exceed 20 times, controller recognize the failure.
-
Controller counts the number of the wheel deceleration of -100g[(-25km/h) for 7ms]. When the numbers at each wheel exceed 56 times, controller recognize the failure.
-
The wheel deceleration of –100g[(-25km/h) for 7ms] causes the controller to start monitoring this failure and to compare the wheel velocity with the vehicle velocity from next cycle. When its difference of -100g is continued for more than 140msec, controller recognize the failure.
-
In case that any sensor failure at other wheel was already detected, When the numbers of 100g at each wheel exceed 5 times, or When the numbers of 40g at each wheel exceed 20 times, controller recognize the failure.
-
The counter of speed jump is cleared every 30min.
Wrong Exciter :
-
Max. wheel velocity exceeds 20km/h and the wheel velocity is 40% of max. wheel velocity. if this condition is lasted for 2 minutes.
-
Max. wheel velocity exceeds 40km/h and the wheel velocity is 60% of max. wheel velocity. if this condition is lasted for 2 minutes. - Faulty installing of wheel speed sensor
-
Open/short in circuit of wheel speed sensor
-
Faulty wheel speed sensor
-
Faulty rotor or wheel bearing
-
Faulty HECU
FAILSAFE FUNCTION
Sensor malfunction without ABS control :
- One wheel sensor malfuntion
Only the ABS, TCS(ESP) functions are inhibited. the ABS, TCS(ESP) warning lamps are ON, but the EBD warning lamp is OFF.
- More than two wheels malfunction
The system stops. the ABS, TCS(ESP) and the EBD functions are inhibited. the ABS, TCS(ESP) and the EBD warning lamps are ON. The valve relay and all solenoids are OFF.
Sensor malfunction with ABS control :
- One front wheel malfunction
Inhibit the ABS control of a wheel with a malfunctioning sensor and maintain the ABS control of other wheels.
After the ABS control has completed, the ABS, TCS(ESP) functions are inhibited. The ABS, TCS(ESP) warning lamps are ON and the EBD warning lamp is OFF.
- One rear wheel malfunction
Inhibit ABS control of both front wheels and the pressure of both rear wheels is decreased.
After the controller completes the ABS control, Only the ABS, TCS(ESP) functions are inhibited. The ABS, TCS(ESP) warning lamps are ON and the EBD warning lamp is OFF.
- More than two wheels malfunction.
The system stops. the ABS, TCS(ESP) and the EBD functions are inhibited. The ABS, TCS(ESP) and the EBD warning lamps are ON. The valve relay and all solenoids are OFF.
INSPECTION PROCEDURE
1.
CHECK AIR GAP BETWEEN WHEEL SPEED SENSOR AND TONE WHEEL.
Visually check the installing of wheel speed sensors and rotors(see the table below)
Specification : 0.5~1.5mm
DTC
Appropriate wheel sensor
C1201
C1204
C1207
C1210
Front - left wheel sensor
Front - right wheel sensor
Rear- left wheel sensor
Rear- right wheel sensor
note
The mounting bolt shall be tightened properly and there is no clearance is allowed between the sensor and front steering knuckle or rear axle carrier.
Is the air gap within the specification?
▶Reinstall or replace, if neccessary, wheel speed sensors in trouble.
▶Check sensor rotor and sensor tip.
2.
CHECK SENSOR ROTOR AND SENSOR TIP
Check visually the sensor rotor and the sensor tip have scratches, missing teeth or foreign objects.
Is it normal?
(1)
Remove foreign objects form the sensor rotor and tip.
(2)
Replace the sensor rotor or the sheel speed sensor.
▶After clearing the DTC and driving the vehicle at 40km/h speed or more, if the TCS(ESP) lamp is ON and the same DTC shows again, replace the HECU and recheck.
