3233038 - F21 ABS NOT WORKING / (ONE WHEEL LOCKED)
When the brakes are operated abruptly without warning (panic braking), the ABS does not work and one wheel will therefore lock | Locking of one wheel could - under certain circumstances - be a normal system reaction (see ABS operation). this is particularly likely on an unsurfaced road. |
| Results of the tests | ||||
| 0 | PRELIMINARY CHECKS | All OK | Problems met | Operation |
|---|---|---|---|---|
| Turn the ignition on and check that the "ABS fault" warning light comes on for about 4 seconds, and then goes out. | Continue to Step 1 | The "ABS fault" warning light comes on and stays on | See table K60 | |
| 1 | CHECK WITH DIAGNOSTIC EQUIPMENT | All OK | Problems met | Operation |
| Connect
the diagnostic equipment (Examiner or other instruments) to the
diagnostic socket Check:
| Continue to Step 2 | An error is detected in the control unit | Continue according to the instructions for the diagnostic equipment | |
| Lack of dialogue with the control unit | Restore the connection between the ABS control unit and the diagnostic connector ( See E7020 ABS ). | |||
| 2 | ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT | All OK | Problems met | Operation |
Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of:
| Continue to Step 3 | Fault detected in one solenoid | Replace electrohydraulic unit-electronic control unit Op. 3340A12 | |
| Fault detected at the front | Replace the sensor Op. 3340A30 | |||
| Fault detected in a rear sensor | Replace the sensor Op. 3340A34 | |||
| Fault detected in a front wheel hub | Replace the wheel hub Op. 4450C28 | |||
| Fault detected in a rear wheel hub | Replace the wheel hub Op. 4450D10 | |||
| 3 | AIR PRESENCE CHECK | All OK | Problems met | Operation |
| Check for presence of air in the system | Continue to Step 4 | Presence of air in the system | Bleed the air from the system Op. 3330A14 | |
| 4 | CHECK CORRECT OPERATION | All OK | Problems met | Operation |
| Check that the fault is no longer present | End of diagnosis | Fault persists | Search for the fault starting from another symptom' | |