ABS

Fig. 18 Code B1381: Wheel Sensor Rear Left, Signal Faulty Or No Signal (Part 1 Of 2):

Fig. 18 Code B1381: Wheel Sensor Rear Left, Signal Faulty Or No Signal (Part 2 Of 2):

Fault symptom
ABS warning lamp on, no ABS function.

Condition
Fault registered at a speed of 10 km/h.

Diagnostic help
The rear 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 rear assembly of the vehicle is lifted the ISAT should display approx. 5 km/h if the left rear 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. Reed WHEEL SPEEDS in accordance with diagnostic help. Compare the four wheel speeds shown.

Does the rear left wheel speed show 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.

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

3 Wheel sensor signal check
- Lift the rear suspension of the vehicle.
- Take a voltage measurement, mVac. at the wheel sensors connector. Connect a voltmeter between the connector pins. Rotate the rear left wheel at approx. 1 turn per second. The wheel sensor voltage should be 100 mVac.

Is the voltage OK?
YES - Continue with point 4.
NO - Change wheel sensor

4 Final Inspection
- Erase the diagnostic trouble code.
- Carry out the driving 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.