Abs not working / (one wheel locked)
- Make
- Fiat
- Model
- 500 Factory Service Manual
- Year
- 2007–2024
- Section
- Brakes › Abs not working / (one wheel locked)
ABS NOT WORKING / (ONE WHEEL LOCKED)
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 | ||||
| 1 | CHECK USING DIAGNOSTIC EQUIPMENT | All OK | Problems encountered | Operation |
|---|---|---|---|---|
Connect the Examiner diagnostic equipment to the diagnostic socket. Check:
| 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 | |
| 2 | ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT | All OK | Problems encountered | Operation |
Keeping the Examiner diagnostic equipment connected, carry out the active diagnosis of:
| Move on to Step 3 | Fault 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. | |
| 3 | PRESENCE OF AIR CHECK | All OK | Problems encountered | Operation |
| Check for the presence of air in the system | Move on to Step 4 | Presence of air in the system. | Bleed the air from the system | |
| 4 | PIPE / HOSE AND BRAKE BLEEDING CHECK | All OK | Problems encountered | Operation |
| Visually inspect that there are no bends or constrictions in the brake pipes. | Move on to Step 5 | Presence of bends or constrictions. | Replace the section of pipe affected by the problem. | |
| 5 | BRAKE CALLIPER CHECK | All OK | Problems encountered | Operation |
| Check the sliding of the brake calliper control pistons | End 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 | |
| 5 | FRONT BRAKE CALLIPERS AND SHOE CONTROL CYLINDER CHECK | All OK | Problems encountered | Operation |
| 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
- TOOLOBD2 scanner with ABSSearch: OBD2 scanner ABS SRS
- TOOLDigital multimeterSearch: automotive digital multimeter
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