2888356 - 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
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket

Check:

  • that there are no faults in the ABS control unit
  • plausibility of all the parameters
Continue to Step 2An error is detected in the control unitContinue according to the instructions for the diagnostic equipment
Lack of dialogue with the control unitRestore the connection between the ABS control unit and the diagnostic connector ( See   E7020  ABS )
2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of:

  • pump motor
  • solenoids
Continue to Step 3Fault detected in one solenoidReplace electrohydraulic unit-electronic control unit Op.   3340A12 
3AIR PRESENCE CHECKAll OKProblems metOperation
Check for presence of air in the systemContinue to Step 4Presence of air in the systemBleed the air from the system Op. 3330A16
4CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'