323001751 - F020 ABS WORKING IRREGULARLY

When the brakes are operated briskly and suddenly (emergency braking) the ABS does not work properly and, as a result, one or more of the wheels is partly locked

		TEST RESULTS
0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Turn the ignition key to MAR and check that the ABS failure warning light comes on for around 4 seconds and then goes off	Move on to Step 1	The ABS failure warning light comes on and stays on.	Proceed as instructed in the    See table K060 ABS FAILURE WARNING LIGHT ON
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the Examiner diagnostic equipment to the diagnostic socket and check:- check that there are no faults in 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 unit3. Fault detected in one of the front sensors.4. Fault detected in one of the rear sensors.5. Fault detected in one of the front wheel hubs.6. Fault detected in one of the rear wheel hubs.	1. Continue following the instructions on the diagnostic equipment2. Restore connection between the ABS control unit and the diagnostic connector    See E7020 ABS 3. Replace the sensor    Op. 3340A30 RPM SENSOR (ONE) FOR ONE FRONT WHEEL, LEFT OR RIGHT - R.R. 4. Replace the sensor    Op. 3340A34 LEFT OR RIGHT REAR WHEEL RPM SENSOR (ONE) - R.R. 5. Replace the wheel hub    Op. 4450C10 FRONT STEERING KNUCKLE (ONE), L/H OR R/H COMPLETE WITH WHEEL HUB - R+R WITH WHEEL REMOVED - CHECK WHEEL GEOMETRY SEPARATELY 6. Replace the wheel hub    Op. 4450D10 HUB FOR ONE REAR WHEEL, L/H OR R/H - R+R WITH WHEEL REMOVED - CHECK WHEEL GEOMETRY SEPARATELY
2	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected carry out the active diagnosis of:- pump motor;- solenoid valves.	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	BRAKE CALLIPER CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the sliding of the brake calliper control pistons.	Move on to Step 4	Front calliper pistons seized.	Replace the front brake callipers    Op. 3310A30 FRONT BRAKE CALIPER (ONE) - R.R
4	PIPE / HOSE AND BRAKE BLEEDING CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Visually inspect that there are no bends or constrictions in the brake pipes, bleed the system and check that the fluid comes out evenly from the bleed screws.	End of diagnosis	Bends or constrictions present, the fluid does not come out evenly.	Replace the section of pipe affected by the problem.