2888354 - F12 BRAKE PEDAL HARD

When the brake pedal is pressed, stiffness is felt during the pedal travel.
Results of the tests
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socketCheck that there are no faults in the ABS control unitContinue to Step 2An error is detected in the control unitContinue according to the instructions for the diagnostic equipment
Lack of dialogue with the control unit

Refit:

  • the connection between the ABS control unit and the diagnostic connector
  • the ABS control unit supply 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
  • soleonoids
Continue to Step 3A fault is detected in the pump or in a solenoid valveReplace electrohydraulic unit-electronic control unit Op.   3340A12 
3CHECK VACUUM PIPEAll OKProblems metOperation
Check condition and fitting of vacuum pipeContinue to Step 4Pipe fitted incorrectly or bentRefit correctly
Pipe damagedReplace the vacuum pipe Op. 3310D24
4CHECK ON NON-RETURN VALVEAll OKProblems metOperation
Check that the non-return valve is working properlyContinue to Step 5Non-return valve not working properlyReplace non-return valve Op.   3330D20 
5CHECK BRAKE SERVOAll OKProblems metOperation
Check that brake servo is working properly: See Test   3330DA  Check operation of brake servo Continue to Step 6Brake servo not working properlyReplace the servo unit Op.   3330D10 
6CHECK ENGINE VACUUMAll OKProblems metOperation
1.9 JTD 8V ABSCheck vacuum in vacuum circuit:Continue to Step 7Vacuum value incorrectReplace brake servo vacuum unit Op.   3330D30 
1.6 16v ABSContinue to Step 7
7CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'
When the brake pedal is pressed, stiffness is felt during the pedal travel.
Results of the tests
1CHECK VACUUM PIPEAll OKProblems metOperation
Check condition and fitting of vacuum pipeContinue to Step 2Pipe fitted incorrectly or bentRefit correctly
Pipe damagedReplace the vacuum pipe Op. 3310D24
2CHECK ON NON-RETURN VALVEAll OKProblems metOperation
Check that the non-return valve is working properlyContinue to Step 3Non-return valve not working properlyReplace non-return valve Op.   3330D20 
3CHECK BRAKE SERVOAll OKProblems metOperation
Check that brake servo is working properly: See Test   3330DA  Check operation of brake servo Continue to Step 4Brake servo not working properlyReplace the servo unit Op.   3330D10 
4CHECK ENGINE VACUUMAll OKProblems metOperation
1.9 JTD 8V [[]Check vacuum in vacuum circuit:Continue to Step 5Vacuum value incorrectReplace brake servo vacuum unit Op.   3330D30 
1.6 16v [[]Continue to Step 5
5CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'