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Fiat 500 Factory Service Manual (2007-2024)22 · Fault diagnosis
22 · Diagnostics

Abs not working / (one wheel locked)

Make
Fiat
Model
500 Factory Service Manual
Year
2007–2024
Section
Brakes › Abs not working / (one wheel locked)
Fault diagnosisAbs not working / (one wheel locked)

ABS NOT WORKING / (ONE WHEEL LOCKED)

1.2 8v, 1.3 Multijet, 1.4 16v

When the brakes are operated briskly and suddenly (emergency braking) the ABS does not work and, as a result, one of the wheels locks

The locking of one of the wheels may, in certain circumstances, be a normal reaction of the system (see operation of the ABS system). This is possible, in particular, on uneven roads

Test results
1CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation

Connect the Examiner diagnostic equipment to the diagnostic socket.

Check:

  • that there are no errors at the ABS control unit;
  • the plausibility of all the parameters
Move on to Step 2

1. Error detected in the control unit.

2. No communication with the control unit.

1. Continue following the instructions on the diagnostic equipment

2. Restore connection between the ABS control unit and the diagnostic connector; see

See E7020 ABS

2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation

Keeping the Examiner diagnostic equipment connected, carry out the active diagnosis of:

  • pump motor;
  • solenoids.
Move on to Step 3Fault detected in one of the solenoid valves.

Replace the electrohydraulic unit - ABS electronic control unit

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

3PRESENCE OF AIR CHECKAll OKProblems encounteredOperation
Check for the presence of air in the systemMove on to Step 4Presence of air in the system.

Bleed the air from the system

Op. 0010T65 HYDRAULIC BRAKE SYSTEM - BLEED AIR

4PIPE / HOSE AND BRAKE BLEEDING CHECKAll OKProblems encounteredOperation
Visually inspect that there are no bends or constrictions in the brake pipes.Move on to Step 5Presence of bends or constrictions.Replace the section of pipe affected by the problem.
5BRAKE CALLIPER CHECKAll OKProblems encounteredOperation
Check the sliding of the brake calliper control pistonsEnd of diagnosis.

1. Front calliper pistons seized.

2. Rear calliper pistons seized.

1. Replace the front brake callipers

Op. 3310A30 FRONT BRAKE CALIPER (ONE) - R.R

2. Replace the rear brake callipers

Op. 3310B36

5FRONT BRAKE CALLIPERS AND SHOE CONTROL CYLINDER CHECKAll OKProblems encounteredOperation
Check that the shoe control cylinder is working properly.End of diagnosis.

1.Front calliper pistons seized.

2.Shoe control cylinder not working properly.

1. Replace the front brake callipers

Op. 3310A30 FRONT BRAKE CALIPER (ONE) - R.R

2.Replace the shoe control cylinder

Op. 3320B20 REAR BRAKE SHOE CYLINDER (ONE) LEFT OR RIGHT - REPLACE.

Parts & tools for this job For 2007 Fiat 500

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