F20 ABS WORKING IRREGULARLY - Alfa - 156 - eLearn

3233037 - F20 ABS WORKING IRREGULARLY

When the brakes are operated vigorously and suddenly ("panic" braking), the ABS does not work properly, so one or more wheels lock(s).

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Turn the ignition on and check that the "ABS fault" warning light comes on for about 4 seconds, and then goes out.	Continue to Step 1	The "ABS fault" warning light comes on and stays on	See table K60
1	CHECK WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket Check: that there are no faults in the ABS control unit plausibility of all the parameters	Continue to Step 2	An error is detected in the control unit	Continue according to the instructions for the diagnostic equipment
		Continue to Step 2	Lack of dialogue with the control unit	Restore the connection between ABS control unit and diagnostic connector ( See E7020 ABS ).
2	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of: pump motor; solenoid valves; speed sensors	Continue to Step 3	Fault detected in the pump or a solenoid	Replace electrohydraulic unit-electronic control unit Op. 3340A12
			Fault detected in a front sensor	Replace the sensor Op. 3340A30
			Fault detected in a rear sensor	Replace the sensor Op. 3340A34
			Fault detected in a front wheel hub	Replace the wheel hub Op. 4450C28
			Fault detected in a rear wheel hub	Replace the wheel hub Op. 4450D10
4	CHECK CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'