22 · Diagnostics

Rear wheels lock whilst braking

Make: Fiat
Model: Multipla Factory Service Manual
Year: 1998–2010
Section: Braking system › Rear wheels lock whilst braking

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Fault diagnosisRear wheels lock whilst braking

REAR WHEELS LOCK WHILST BRAKING

When the brakes are operated, the distribution between front and rear wheels is not correct: at worst, the rear wheels may lock and the car may skid

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Carry out a preliminary check to see whether the ABS and handbrake warning lights come on simultaneously during starting and then go out.	Continue to Step 1	After starting, the two warning lights remain on	See table K62 ABS AND HANDBRAKE WARNING LIGHTS BOTH ON
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.	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 the ABS control unit and the diagnostic connector the ABS control unit supply 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 solenoids	Continue to Step 3	Fault detected in one solenoid	Replace electrohydraulic unit-electronic control unit Op. 3340A12
3	CHECK BRAKE PIPES/HOSES AND BLEEDING	All OK	Problems met	Operation
	Visually check that there are no kinks or restrictions in the brake pipes, bleed the system Op. 3330A18and check that fluid emerges from the bleed screws as normal	Continue to Step 4	There are kinks or restrictions, fluid does not come out normally	Replace the section of pipe affected by the fault (see Assembly 3340B)
4	CHECKING 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'

When the brakes are operated, the distribution between front and rear wheels is not correct: at worst, the rear wheels may lock and the car may skid

1	LOAD PROPORTIONING VALVE CHECK	All OK	Problems met	Operation
		Results of the tests
	Check that the rear load proportioning valve is correctly calibrated Op. 3330C62	Continue to Step 2	Load proportioning valve incorrectly calibrated	Restore the calibration Op. 3330C62
		Continue to Step 2	Load proportioning valve faulty	Replace the load proportioning valve Op. 3330C60
2	CHECK BRAKE PIPES/HOSES AND BLEEDING	All OK	Problems met	Operation
	Visually check that there are no kinks or restrictions in the brake pipes, bleed the system Op. 3330A18and check that fluid emerges from the bleed screws as normal	Continue to Step 3	There are kinks or restrictions, fluid does not come out normally	Replace the section of pipe which is faulty (see Assembly 3330E)
3	CHECKING 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'

‹ Prev Poor braking action Next › Excessive brake pedal free play

Parts & tools for this job For 1998 Fiat Multipla

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