22 · Diagnostics

Engine idle irregular

Make: Fiat
Model: Croma Factory Service Manual
Year: 2005–2010
Section: Engine › Engine idle irregular

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Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

1.9 JTD 8v, 1.9 JTD 16v, 2.4 JTD 20v

The customer complains of: Irregular idling/vibrations

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	Check that the engine oil level is correct Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY Check that the air intake/vacuum circuit is working properly by carrying out the See Test 1048OA AIR INTAKE/VACUUM CIRCUIT CHECK Check the condition of the fuel supply circuit and make sure that it is working properly carrying out the See Test 1040OA FUEL SUPPLY CIRCUIT CHECK Check the operation of the low pressure supply circuit by carrying out the See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT	Move on to Step 1	Oil level incorrect	Restore the correct engine oil level Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY
1	AMBIENT PARAMETERS CHECK	All OK	Problems encountered	Operation
	Select the following control unit at the diagnostic equipment: EDC16C39 Diesel electronic injection control unit. Check the value of the following parameters: . Battery voltage See Test 5530BB BATTERY VOLTAGE CHECK . Accelerator pedal . Accelerator position 1 AD/C . Accelerator position 2 AD/C See Test 1068AC ACCELERATOR PEDAL CHECKS . Target Diesel pressure . Measured Diesel pressure See Test 1060GH DIESEL FUEL PRESSURE CHECK . Engine rpm See Test 1060GI ENGINE SPEED CHECK . Measured air mass See Test 1060GG MEASURED AIR MASS CHECK . Engine coolant temperature See Test 1060OE CHECK ON OPERATION OF COOLANT TEMPERATURE SENSOR	Move on to Step 2
2	PREHEATING RELAY ACTIVE DIAGNOSIS	All OK	Problems encountered	Operation
	Carry out the active diagnosis for the preheating relay, checking that the result is positive. The check on the following system is only necessary if the outside temperature is below 0 °C.	Move on to Step 4	The result of the active diagnosis is negative	Move on to Step 3
3	HEATER PLUGS CHECK	All OK	Problems encountered	Operation
	Check that the heater plugs are working properly, by carrying out the See Test 5520CA GLOW PLUGS FUNCTIONAL TEST	Move on to Step 4
4	ELECTRICAL EQUIPMENT CHECK	All OK	Problems encountered	Operation
	Check that the fuses F1 (the last one at the bottom of the vertical row) and F20 (the first one on the right of the lower row) have not blown	Move on to Step 6	Fuse F1 has blown	Restore the connections or, if necessary, replace the junction unit in the engine compartment Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.
		Move on to Step 6	Fuse F20 has blown	Move on to Step 5
5	DIESEL PREHEATING FUSE CHECK	All OK	Problems encountered	Operation
	Check the circuit for the protective fuse for the diesel preheating relay, by carrying out the See Test 5505AB CHECK DIESEL PREHEATING RELAY PROTECTIVE FUSE	Move on to Step 6
6	DIESEL PREHEATING RELAY CHECK	All OK	Problems encountered	Operation
	Check the diesel preheating relay circuit, by carrying out the See Test 5505AC CHECK DIESEL PREHEATING RELAY	End of diagnosis
7	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Carry out the active diagnosis for the E.G.R. solenoid valve	Move on to Step 8	Solenoid valve not working	Restore the wiring continuity See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the solenoid valve if necessary Op. 1080C24 E.G.R. SYSTEM SOLENOID - R + R
8	FUEL FILTER CHECK	All OK	Problems encountered	Operation
	Check fuel filter operation	Move on to Step 9	Water, petrol, paraffin or dirt found to be present	Clean the tank and pipes and replace the diesel filter cartridge Op. 1044B20 FUEL FILTER FILTERING ELEMENT - REPLACE
9	VALVE CLEARANCE CHECK	All OK	Problems encountered	Operation
	Check that the tappet clearance is correct Op. 1036H10 VALVE TAPPETS - CHECK AND ADJUST CLEARANCE, IF NECESSARY	Move on to Step 10	Valve clearance not correct	Adjust the tappets
10	CYLINDER COMPRESSION CHECK	All OK	Problems encountered	Operation
	Carry out the cylinder compression check Op. 0520G15 COMPRESSION TEST - CHECK WITH EXAMINER WITH SPARK PLUGS/INJECTORS REMOVED	Move on to Step 12	Cylinder compression insufficient	Move on to Step 11
11	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	All OK	Problems encountered	Operation
	Carry out Op. 1016C10 SINGLE CYLINDER HEAD - R.R. AND REPLACE GASKET to check the valve seal and check the condition of the cylinders/piston rings	Move on to Step 12	Valve seal insufficient	Overhaul the cylinder head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
12	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Replace the engine management control unit Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R

1.8, 2.2

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	First, check: status of spark plugs and leads; condition of the air filter; the condition of the air intake circuit	Move on to Step 1	Spark plugs dirty or defective	Replace the spark plugs Op. Op. 5510D10 SPARK PLUGS - R+R
			Leads defective	Replace spark plug leads
			Air filter blocked	Replace the filter element Op. Op. 1048A14 AIR CLEANER FILTER ELEMENT - REPLACE.
			Fault in the air intake circuit	Restore the correct operation of the intake circuit
1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Connect the diagnostic test equipment (Examiner or other instruments) to the tester input. Check: that there are no faults in the engine management control unit; parameter plausibility	Move on to Step 2	"Fuel system" error detected	See table Z50 ERRORE TITOLO MISCELA
			Another error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameter not consistent	Continue following the instructions for the diagnostic equipment
2	IDLE ACTUATOR CHECK	All OK	Problems encountered	Operation
	Check the system conducts the correct idle initialisation procedure	Move on to Step 3	Irregular idle	Carry out the correct idle initialisation procedure
3	PETROL VAPOUR RECOVERY SYSTEM CHECK	All OK	Problems encountered	Operation
	Check the petrol vapour recovery pipe condition and seal	Move on to Step 4	Air leaks	Restore the correct seal
			Pipe from filter to intermediate joint broken	Replace the pipe Op. Op. 1080E50 INTERMEDIATE FUEL VAPOUR PIPE R R
			Pipe from intermediate joint to solenoid 1. Restore the correct seal	Replace the pipe Op. Op. 1080E66 AIR INTAKE CHAMBER FUEL VAPOUR INTAKE PIPE - R.R.
4	PETROL VAPOUR RECOVERY SOLENOID VALVE CHECK	All OK	Problems encountered	Operation
	Carry out the active diagnosis of the solenoid valve	Move on to Step 6	Solenoid valve not working	Move on to Step 5
5	SOLENOID VALVE ELECTRICAL CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check the petrol vapour recovery solenoid valve supply and earth. See See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT	Move on to Step 6	Solenoid valve faulty	Replace the solenoid Op. Op. 1080E28 ENABLEMENT SOLENOID FOR FLOW OF FUEL VAPOUR TO INLET - R+R
		Move on to Step 6	Connections not correct	Repair the connections See See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
6	BRAKE SERVO AND PIPE CHECK	All OK	Problems encountered	Operation
	Check condition of: brake servo vacuum pipes; brake servo	Move on to Step 7	Brake servo pipe defective	Replace the pipe Op. Op. 3330D26 VACUUM PIPE FOR BRAKE SERVO ASSEMBLY - R.R
	Check condition of: brake servo vacuum pipes; brake servo	Move on to Step 7	Brake servo defective	Replace the brake servo/pump assembly Op. Op. 3330D02 BRAKE SERVO/BRAKE PUMP ASSEMBLY - R.R.
7	FUEL PRESSURE CHECK	All OK	Problems encountered	Operation
	Check the fuel supply pressure Op. Op. 0510C10 FUEL SYSTEM - CHECK DELIVERY PRESSURE	Move on to Step 8	Fuel pressure too low: pipe obstructed	Eliminate the obstructions, if necessary replace the pipe Op. Op. 1040B32 FRONT FUEL DELIVERY LINE - R.R.
			Fuel pressure too low: filter blocked	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
			Fuel pressure too low: regulator blocked	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
			Fuel pressure too low: pump defective	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
8	PHASE TRANSFORMER SOLENOID VALVE CHECK	All OK	Problems encountered	Operation
	Carry out the active diagnosis of the phase transformer solenoid valve	Move on to Step 10	Solenoid valve not working	Move on to Step 9
9	PHASE TRANSFORMER ELECTRICAL CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check the supply and earth for the phase transformer solenoid valve See See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT	Move on to Step 10	Phase transformer faulty	Replace the phase transformer Op. Op. 1036C41 PHASE TRANSFORMER ON OVERHEAD CAMSHAFT (ONE) INTAKE EXHAUST ON CYLINDER HEAD - R.R.
		Move on to Step 10	Connections not correct	Repair the connections See See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
10	PHASE TRANSFORMER CHECK	All OK	Problems encountered	Operation
	Check the operation of the phase transformer supplying the phase transformer solenoid valve directly. The engine speed should vary considerably (very irregular idling)	Move on to Step 11	There are no speed variations: phase transformer stuck	Replace the phase transformer Op. Op. 1036C41 PHASE TRANSFORMER ON OVERHEAD CAMSHAFT (ONE) INTAKE EXHAUST ON CYLINDER HEAD - R.R.
11	TIMING CHECK	All OK	Problems encountered	Operation
	Check that the valve gear timing is correct	Move on to Step 12	Valve gear timing not correct	Restore the correct valve gear timing Op. Op. 1032B10 TOOTHED TIMING BELT - R + R FOR TIMING ADJUSTMENT OR REPLACEMENT
12	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present	End of diagnosis	The fault persists: control unit defective	Replace the control unit Op. Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R

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Parts & tools for this job For 2005 Fiat Croma

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