DTC 2-3-1 L/H Front Wheel Sensor, Signal Absent

CONDITIONS FOR DTC
If a sensor signal is missing, the control module detects the fault on the move and posts the DTC. It detects the fault by comparing the different wheel speeds.

SYMPTOMS
ABS warning light on, ABS system out of action.

SOURCES OF FAULT
^ Short-circuit in wheel sensor or lead to ground.
^ Spacing between sensor and pulse wheel too large.
^ Pulse wheel installed incorrectly.
^ Sensor installed incorrectly.

CHECKING VOLTAGE
1. Ignition off.
2. Connect test box between control module and ABS system connector.
3. Jack car up so wheel is free to turn.
4. Connect a voltmeter (set to AC) across test box terminals as follows: LH front wheel, # 4 (0 volts) and # 6
5. Ignition on.
6. Turn the wheel concerned by hand. If checking rear wheel sensor, make sure that other wheel is locked.
7. Voltmeter reading should vary between 0 and 2 volts, depending on wheel speed. At low wheel speeds, meter should read approx. 500 mV.

IF READING IS INCORRECT
If voltmeter reads 0 volts, there is a short-circuit in the sensor or lead. Go to Checking lead resistance to ground.

CHECKING LEAD RESISTANCE TO GROUND
1. Ignition off.
2. Disconnect connector from the sensor concerned.
3. Using an ohmmeter, take readings across test box terminals as follows: LH front wheel, # 20 and # 6
4. Ohmmeter reads infinite resistance: Lead is OK. Go to Checking sensor.
5. Ohmmeter reads 0 ohms: Short-circuit in lead. Repair short-circuit. Check DTC after repair is done.

CHECKING SENSOR
1. Ignition off.
2. Remove connector from sensor.
3. Connect an ohmmeter across sensor pins.
4. Ohmmeter should read: LH front wheel 1 ohm

IF READING IS INCORRECT
If ohmmeter reading is 0 ohms sensor is short-circuited. Replace sensor and connect components. Check DTC after action.

IF READING IS CORRECT
Go to Checking pulse wheel.

CHECKING PULSE WHEEL
1. Jack car up.
2. Check that pulse wheel is not damaged.

NOTE: A damaged pulse wheel will mean faulty signals to the control module.

3. Check:
^ that the pulse wheel is fitted correctly
^ that the pulse wheel is not damaged