ABS

Fig. 14 Code B1371: Wheel Sensor Front Left, Signal Faulty (Part 1 Of 2):

Fig. 14 Code B1371: Wheel Sensor Front Left, Signal Faulty (Part 2 Of 2):

Fault symptom
ABS warning lamp on, no ABS function.

Condition
Fault registered as open-circuit with a speed of 40 km/h.

Diagnostic help
- The front left wheel sensor can be read by ISAT.
- Select "READ FUNCTIONS"
- Select "WHEEL SPEEDS"

The current wheel speed in km/h is displayed.
- If the front assembly of the vehicle is lifted the ISAT should display approx. 5 km/h if the left front wheel is rotated by hand at approx. 1 turn per second.

Diagnostic procedure
1 Diagnostic Trouble Code inspection
- Connect the ISAT Scan Tool.
- Start and test drive the car at an even speed. Read WHEEL SPEEDS in accordance with diagnostic help. Compare the four wheel speeds shown.

Does the front left wheel wheel have a faulty rating?
YES - Continue with point 2.
NO - Continue with point 4.

2 Mechanical size inspection.
Check that:
- wheel size and tire pressure are correct.
- there is no wheel bearing play.
- the toothed wheel is not damaged.

Is the inspection OK?
YES - Continue with point 3.
NO - Rectify the fault

3 Toothed wheel air gap inspection
- Check that the air gap between the toothed wheel and the wheel sensor is O.6+/-0.3 mm.

Is the air gap correct?
YES - Continue with point 4.
NO - Rectify the fault

4 Final inspection
- Erase the diagnostic trouble code.
- Carry out the drive cycle, drive the car with various load and engine speeds for 5 minutes.
- Read the diagnostic trouble code.

Is the diagnostic trouble code stored?
YES - Continue With "Test Procedure Prior To Replacing "ECM"
NO - The diagnostic procedure performed is right or the fault is of intermittent character.