F021 ABS NOT WORKING / (ONE WHEEL LOCKED) - Fiat - NUOVA 500 - eLearn

312000219 - F021 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

1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
		Test results
	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 equipment2. Restore connection between the ABS control unit and the diagnostic connector; see See E7020 ABS
2	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Keeping the Examiner diagnostic equipment connected, carry out the active diagnosis of: pump motor; solenoids.	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 Op. 0010T65 HYDRAULIC BRAKE SYSTEM - BLEED AIR
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 callipersOp. 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.