Engine not running smoothly / (irregular operation)

Make: Fiat
Model: Croma Factory Service Manual
Year: 2005–2010
Section: Engine › Engine not running smoothly / (irregular operation)

‹ Prev Engine not running smoothly / (losing power)Next › Engine not running smoothly

Fault diagnosisEngine not running smoothly / (irregular operation)

ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

1.9 JTD 8v, 1.9 JTD 16v

The customer complains of: The engine is not running smoothly

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 See Test 1048OA AIR INTAKE/VACUUM CIRCUIT CHECK Check the condition of the fuel supply circuit and make sure that it is working properly See Test 1040OA FUEL SUPPLY CIRCUIT CHECK Check the operation of the low pressure supply circuit See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT Check the fastening of the battery earth terminal	Move on to Step 1	Oil level incorrect Battery earth terminal insecure	Restore the correct engine oil level See Test 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY Restore the correct earth lead fastening See E1020 EARTHS
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 . Engine coolant temperature See Test 1060OE CHECK ON OPERATION OF COOLANT TEMPERATURE SENSOR . Diesel temperature See Test 1060EA DIESEL FUEL TEMPERATURE CHECK . Measured air mass See Test 1060GG MEASURED AIR MASS CHECK . Engine rpm See Test 1060GI ENGINE SPEED CHECK Reach a constant speed of around 30 km/h and check that the reading on the diagnostic equipment for the vehicle speed coincides more or less with the speed shown on the instrument panel	Move on to Step 4	The vehicle speed is not measured correctly	Move on to Step 2
2	ABS CHECKS	All OK	Problems encountered	Operation
	Select the following control unit at the diagnostic equipment: ABS TRW EBC 430NG control unit Check that the system is working properly See Test 3340AB SPEED SIGNAL CHECK	Move on to Step 3
3	SOFTWARE VERSION CHECK	All OK	Problems encountered	Operation
	Check the software version of the EDC16C39 Diesel electronic injection control unit See Test 1060GJ ENGINE MANAGEMENT CONTROL UNIT SOFTWARE RELEASE CHECK	Move on to Step 4
4	CLIMATE CONTROL SYSTEM CHECKS	All OK	Problems encountered	Operation
	Select the following control unit at the diagnostic equipment: EDC16C39 Diesel electronic injection control unit. Check that the system is working properly See Test 5040OB CHECK ON OPERATION OF AIR CONDITIONING SYSTEM (PRESSURE)	Move on to Step 5
5	PREHEATING RELAY ACTIVE DIAGNOSIS	All OK	Problems encountered	Operation
	Carry out the active diagnosis for the preheating relay, checking that the result is positive.	Move on to Step 7	The result of the active diagnosis is negative	Move on to Step 6
6	HEATER PLUGS CHECK	All OK	Problems encountered	Operation
	Check that the heater plugs are working properly See Test 5520CA GLOW PLUGS FUNCTIONAL TEST	Move on to Step 7
7	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 9	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 9	Fuse F20 has blown	Move on to Step 8
8	DIESEL PREHEATING FUSE CHECK	All OK	Problems encountered	Operation
	Check the circuit for the protective fuse for the diesel preheating relay See Test 5505AB CHECK DIESEL PREHEATING RELAY PROTECTIVE FUSE	Move on to Step 9
9	DIESEL PREHEATING RELAY CHECK	All OK	Problems encountered	Operation
	Check the diesel preheating relay circuit See Test 5505AC CHECK DIESEL PREHEATING RELAY	End of diagnosis

1.8, 2.2

Engine judders when car is in motion and is not efficient.

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	First, check: condition of the air filter; status of spark plugs and leads; battery correctly fastened to earth See See E5010 STARTING AND RECHARING	Move on to Step 1	Filter element dirty, damaged or not correctly fitted	Replace or restore the correct filter element fitting Op. Op. 1048A14 AIR CLEANER FILTER ELEMENT - REPLACE.
			Spark plugs dirty or damaged	Replace the spark plugs Op. Op. 5510D10 SPARK PLUGS - R+R
			Spark plug leads damaged	Replace spark plug leads
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
			"Misfire" error detected	See table Z56 ERRORE SEGNALE LAMBDA A MONTE
			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	ROAD TEST USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Carry out a road test reproducing the conditions in which the fault occurs, keeping the diagnostic equipment connected. Check: that there are no faults in the engine management control unit; parameter plausibility	Move on to Step 3	"Fuel system" error detected	See table Z50 ERRORE TITOLO MISCELA
			"Misfire" error detected	See table Z56 ERRORE SEGNALE LAMBDA A MONTE
			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
3	FUEL PRESSURE CHECK	All OK	Problems encountered	Operation
	Check the fuel supply pressure, if necessary on the road (to reproduce the conditions in which the problem occurs) Op. Op. 0510C10 FUEL SYSTEM - CHECK DELIVERY PRESSURE	Move on to Step 4	Pressure not correct: obstructions in the fuel supply pipe	Remove the obstructions in the fuel pipe, replace it if necessary Op. Op. 1040B32 FRONT FUEL DELIVERY LINE - R.R.
			Pressure not correct: tank not sufficiently ventilated	Restore the tank ventilation
			Pressure not correct: fuel pump electric circuit interrupted	Restore fuel pump electric circuit See See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
			Pressure not correct: petrol pump damaged	Replace the petrol pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
4	AIR CONDITIONING SYSTEM CHECK	All OK	Problems encountered	Operation
	Road test the vehicle, checking that the irregular behaviour does not occur when the air conditioning is switched on or off	Move on to Step 5	Fault only present with the air conditioning switched on	See table See table L010 CLIMATE CONTROL NOT COOLING
5	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present		The fault persists: control unit defective	Replace the control unit Op. Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R Search for the fault starting from another symptom

‹ Prev Engine not running smoothly / (losing power)Next › Engine not running smoothly

Parts & tools for this job For 2005 Fiat Croma

Links open Amazon search results in a new tab. As an Amazon Associate I earn from qualifying purchases.