22 · Diagnostics

The vehicle jerks

Make: Alfa Romeo
Model: GT Factory Service Manual
Year: 2003–2010
Section: Gear shift › The vehicle jerks

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Fault diagnosisThe vehicle jerks

THE VEHICLE JERKS

1.8 T.SPARK, 2.0 JTS

It shudders when setting off from a standstill

It shudders during a gear change

Preliminary check: If the vehicle has faults in other systems (warning lights in instrument panel relating to: engine management, ABS, VDC) check the causes of these problems. If this is not the case, proceed with the following chart

0	OIL LEVEL CHECK	All OK	Problems met	Operation
		Results of the tests
	Check the oil level as described in See Test See Test 2127B OIL LEVEL CHECK	Continue to Step 2	Level below the Max reference	Top up the oil level Continue to Step 1
		Continue to Step 2	Level above the Max reference	Reduce to the Max level Continue to Step 2
1	CHECK FOR OIL LEAKS	All OK	Problems met	Operation
	Check that there are no oil leaks as described in See Test See Test 2127C HYDRAULIC GEAR SELECTION SYSTEM	Continue to Step 2	OIl leaks detected	Replace/repair the parts concerned, and top up the oil level Continue to Step 1
2	OIL PRESSURE CHECK	All OK	Problems met	Operation
	Check the oil pressure as described in See Test See Test 2127D OIL PRESSURE CHECK	Continue to Step 4	Pressure < 40 bar	Continue to Step 3
3	ELECTRIC PUMP OPERATION CHECK	All OK	Problems met	Operation
	Check the correct operation of the pump as described in See Test See Test 2127E ELECTRIC SPEED SELECTION SYSTEM	Continue to Step 4	Voltage below 11 V	Check the battery Continue to Step 3
		Continue to Step 4	It is not possible to make gear changes from the lever	Activate the ''clutch bleed'' service from the Examiner Plus or Smart to activate the pump Continue to Step 4
4	CONTROL UNIT ERRORS CHECK	All OK	Problems met	Operation
	Check that there are no control unit errors. In particular: Clutch position sensor CAN message errors (reception/transmission)	Continue to Step 6	Presence of one or more of the errors included in the list	Continue to Step 5
5	CHECKS ON FAULTS DETECTED	All OK	Problems met	Operation
	Check the faults in accordance with See Test See Test 2127I What to do for error in Selespeed control unit	Continue to Step 6	Faulty connections	Repair/replace the wiring Continue to Step 6
		Continue to Step 6	One of the control units does not dialogue (Errors on CAN network)	Repair/replace the control unit concerned Continue to Step 6
6	POTENTIOMETER REPLACEMENT	All OK	Problems met	Operation
	If there is a clutch sensor error and no faults are detected in the connections/wiring, replace the clutch potentiometer Op. 2127E44 and check that the position reading is correct by carrying out a series of C.M.	Continue to Step 7
7	AFTER THE CHECKS ON THE FAULTS DETECTED	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	The fault persists	Continue to Step 8
8	BLEED THE SYSTEM USING THE EXAMINER	All OK	Problems met	Operation
	In active diagnosis carry out two system bleeding cycles using the ''clutch bleed'' command	Continue to Step 9
9	CARRY OUT CLUTCH PARAMETER CALIBRATION USING THE EXAMINER	All OK	Problems met	Operation
	In active diagnosis carry out the calibration of the clutch parameters through the ''clutch self-calibration enablement''	Continue to Step 10
10	ROAD TEST	All OK	Problems met	Operation
	Carry out a road test to check that the fault is no longer present	End of diagnosis	The fault persists	Continue to Step 11
11	FURTHER CHECKS ON OTHER SYSTEMS	All OK	Problems met	Operation
	Check that the problem has not been caused by other systems such as the engine, fuel system	Continue to Step 12	There are faults on other vehicle systems	Continue in accordance with the appropriate diagnostic table
12	THE FAULT PERSISTS	All OK	Problems met	Operation
	Contact Technical Service for further information on the problem	End of diagnosis

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Parts & tools for this job For 2003 Alfa Romeo GT

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