Code No.11, 12,
13, 14: Wheel Speed Sensor (FR, FL, RR, RL) Open Circuit or Short Circuit Code No.21,
22, 23, 24: Wheel Speed Sensor (FR, FL, RR, RL) System
<L.H.drive vehicles> <R.H.drive vehicles>
OPERATION
A toothed rotor generates a voltage signal 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 rotor teeth and the wheel speed sensor, and by the speed of rotation.
The wheel speed sensors transmit the frequency of the voltage signal to the ABS-ECU.
The ABS hydraulic unit modulates the amount of braking force individually applied
to each wheel cylinder.
DIAGNOSIS CODE SET CONDITIONS
Diagnosis codes No.11, 12, 13, 14, 21, 22, 23, and 24 are set in the following cases. Code No.11, 12, 13, 14
When sensor impedance is varies due to breakage of the wiring harness, connectors
or coil of the four wheel speed sensors.
Code No.21, 22, 23, 24
Although no open circuit is found, no input signal from the wheel speed sensors
of one or more wheels is received.
Any abnormality is found with the input signals from the wheel speed sensors.
PROBABLE CAUSES
Code No.11, 12, 13, 14
Malfunction of the wheel speed sensor
Damaged wiring harness or connector
Malfunction of the ABS-ECU
Code No.21, 22, 23, 24
Malfunction of the rotor
The gap between the wheel speed sensor and the rotor is excessive.
Malfunction of the wheel speed sensor
Damaged wiring harness or connector
Malfunction of the ABS-ECU
Front hub assembly is defective <diagnosis code No. 21, 22>
Rear hub assembly is defective <diagnosis code No. 23, 24>
DIAGNOSIS
STEP 1. M.U.T.-III data list
(1)
caution
Before connecting or disconnecting the M.U.T.-III,
turn the ignition switch to the "LOCK" (OFF) position.
Connect M.U.T.-III to the 16-pin diagnosis connector.
(2)Start the engine.
(3)Set M.U.T.-III to the data reading mode, and check the data list items by driving
the vehicle.
Item 1 (Code No.11 is set): Front right wheel speed sensor
Item 2 (Code No.12 is set): Front left wheel speed sensor
Item 3 (Code No.13 is set): Rear right wheel speed sensor
Item 4 (Code No.14 is set): Rear left wheel speed sensor
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q.
Does the speedometer indication match the M.U.T.-III indication?
Go to Step 8.
Go to Step 2.
STEP 2. Check the installation condition of the wheel speed sensors.
Check whether the front right wheel speed sensor or its mounting bolts are loosened.
Q.
Is the check result normal?
Go to Step 3.
Reinstall the wheel speed sensor correctly.
STEP 3. Inspect the wheel speed sensor.
Check the wheel speed sensor relevant to the diagnosis code. For the applicable inspection
procedure, refer to .
Q.
Is the check result normal?
Go to Step 4.
Replace the wheel speed sensor.
STEP 4. Resistance measurement at ABS-ECU connector D-251.
(1)Disconnect the connector D-251.
(2)Measure the resistance between the ABS-ECU connector terminals.
Code No.11 or 21 is set: Between the terminal No.10 and 23
Code No.12 or 22 is set: Between the terminal No.7 and 20
Code No.13 or 23 is set: Between the terminal No.8 and 21
Code No.14 or 24 is set: Between the terminal No.9 and 22
Standard Value: 1.0 - 1.5 kΩ
Q.
Is the check result normal?
Go to Step 8.
NO (When resistance between the terminals No.10 and 23 is not within the standard value.) : Go to Step 5.
NO (When resistance between the terminals No.7 and 20 is not within the standard value.) : Go to Step 6.
NO (When resistance between the terminals No.8 and 21 is not within the standard value.) : Go to Step 7.
NO (When resistance between the terminals No.9 and 22 is not within the standard value.) : Go to Step 7.
STEP 5. Inspect the wheel speed sensor (FR) output line for open or
short circuit.
Check the following items. For inspection service points, refer to .
Resistance between wheel speed sensor terminals
Insulation resistance of wheel speed sensor
Rotor tooth check
Q.
Is the check result normal?
Go to Step 10.
Replace the wheel speed sensor or rotor.
STEP 10. Check the wheel bearing for looseness.
note
If the wheel bearing is loose, the gap between the wheel speed sensor and rotor may become
excessive. Check the hub assembly, for looseness.
When code No.11 or 21 is set: Check the front hub assembly <Refer
to GROUP 26, Hub and knuckle assembly inspection (RH) >.
When code No.12 or 22 is set: Check the front hub assembly <Refer to GROUP
26, Hub and knuckle assembly inspection (LH) >.
When code No.13 or 23 is set: Check the rear hub assembly <Refer to GROUP
27, Rear axle hub assembly inspection (RH) >.
When code No.14 or 24 is set: Check the rear hub assembly <Refer to GROUP
27, Rear axle hub assembly inspection (LH) >.
Q.
Is the check result normal?
Go to Step 11.
NO (front wheel bearing backlash is not within the standard value) : Replace the front hub assembly (Refer to GROUP 26, Hub and knuckle assembly disassembly and
reassembly ).
NO (rear wheel bearing backlash is not within the standard value) : Replace the rear hub assembly (Refer to GROUP 27, Rear axle hub and knuckle assembly disassembly
and reassembly ).
STEP 11. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set.
(1)Drive the vehicle with speed exceeds 8 km/h to recognize wheel signals
to the ABS-ECU.
(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)Disconnect the M.U.T.-III.
(6)Drive the vehicle with speed exceeds 40 km/h to recognize wheel signals
to the ABS-ECU.
(7)Check if the diagnosis code is reset.
(8)Turn the ignition switch to the "LOCK" (OFF) position.
Q.
Is code No.11, 12, 13, 14, 21, 22, 23 or 24 set?
Replace the ABS-ECU.
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 .
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Go to Step 8.
Go to Step 2.
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: Go to Step 5.