Workshop Manuals Factory service & repair Alfa Romeo
Alfa Romeo 159 Factory Service Manual (2005-2011)23 · Fault diagnosis
23 · Diagnostics

Brake pedal hard

Make
Alfa Romeo
Model
159 Factory Service Manual
Year
2005–2011
Section
Brakes › Brake pedal hard
Fault diagnosisBrake pedal hard

BRAKE PEDAL HARD

When the brake pedal is pressed there is a hardening in the pedal travel

1CHECK USING DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION

Connect the diagnostic test equipment (Examiner or other instruments) to the tester input.

Check that there are no faults in the ABS control unit.

Move on to Step 21. Error detected in the control unit1. Continue following the instructions for the diagnostic equipment
2. No communication with the control unit.

2. Restore:

  • Connection between the ABS control unit and the diagnostic connector
  • ABS control unit supply

See E7020 ABS

2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTALL OKPROBLEMS ENCOUNTEREDACTION

Connect the diagnostic equipment (Examiner or other instruments) and carry out the active diagnosis for:

  • Pump motor;
  • Solenoid valves.
Move on to Step 3Fault detected in the pump or in a solenoid valve.

Replace the electronic control unit electrohydraulic unit

Op. 3340A12 ABS HYDRAULIC AND ELECTRONIC CONTROL UNIT - R.R.

3VACUUM PIPE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check that the vacuum pipe is correctly fitted/in good condition.Move on to Step 41. Pipe not fitted correctly or bent1. Refit correctly
2. Pipe damaged.

2. Replace vacuum pipe

Op. 3330D24

4BRAKE SERVO SINGLE-ACTING VALVE CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check that the brake servo single-acting valve is working properly.Move on to Step 5Single-acting valve not working properly.

Clean the one-way valve if it is fouled or dirty, or else replace it.

Op. 3330D20 SINGLE-ACTING VALVE FOR BRAKE SERVO - R+R

5BRAKE SERVO VACUUM CHECKALL OKPROBLEMS ENCOUNTEREDACTION

Check the condition of the brake servo vacuum unit.

Check the condition of the vacuum pipe and the connectors and bands

Move on to Step 61. Brake servo vacuum unit faulty

1. Replace the brake servo vacuum unit.

Op. 3330D30 VACUUM PUMP - R+R

2. Pipe damaged.2. Renew the fastenings or replace the vacuum pipe
6BRAKE SERVO CHECKALL OKPROBLEMS ENCOUNTEREDACTION

Check that the brake servo is working properly.

See Test 3330DA CHECK VACUUM PUMP OPERATION AND BRAKE SERVO VACUUM CIRCUIT

End of diagnosisBrake servo not working properly.

Replace brake servo

Op. 3330D10

Parts & tools for this job For 2005 Alfa Romeo 159

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