22 · Diagnostics

Engine idle irregular

Make: Fiat
Model: Bravo Factory Service Manual
Year: 2007–2014
Section: Engine › Engine idle irregular

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Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

1.4 16v

The engine idle speed is not correct or the engine does not stick to the idle speed

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
	First, check for: -leaks from the manifold gasket; -leaks from the throttle body; -leaks from the cylinder head.	Move on to Step 1	Leaks from the manifold gasket	Restore the gasket
			Leaks from the throttle body gasket	Restore the gasket
			Leaks from the cylinder head	Eliminate the leak
1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket and check: - that there are no errors in the engine management control unit; - parameter plausibility	Move on to Step 2	Error detected in the control unit	Continue following the instructions on the diagnostic equipment
		Move on to Step 2	Parameter not consistent	Continue following the instructions on the diagnostic equipment
2	PETROL VAPOUR RECOVERY SOLENOID CHECK	All OK	Problems encountered	Operation
	Carry out an active diagnosis of the solenoid valve	Move on to Step 4	Solenoid not working	Move on to Step 3
3	VAPOUR SOLENOID ELECTRICAL CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check the wiring between the valve and the engine compartment control unit Check the wiring between the valve and the control unit See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT	Move on to Step 4	Solenoid faulty	Replace the solenoid valve Op. 1080E20 ACTIVE CARBON FILTER FOR FUEL VAPOURS - R + R
		Move on to Step 4	Connections not correct	Restore the correct connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
4	IGNITION SYSTEM CHECK	All OK	Problems encountered	Operation
	Inspect the spark plugs and check that they are working properly Check that the coils are working by carrying out Test_5510CI	Move on to Step 5	Spark plugs defective	Replace spark plugs Op. 5510D10 SPARK PLUGS - R+R
		Move on to Step 5	Coil defective	Replace coil Op. 5510C14 IGNITION COIL/S - R.R.
5	FUEL PRESSURE CHECK	All OK	Problems encountered	Operation
	Check the fuel supply pressure Op. 0520G46 FUEL SYSTEM - CHECK SUPPLY PRESSURE USING THE EXAMINER	Move on to Step 6	Fuel pressure too low: pipe obstructed	Eliminate the obstructions; if necessary, replace the pipe
		Move on to Step 6	Fuel pressure too low: pump defective	Replace the pump assembly Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
6	ENGINE TEMPERATURE CHECK	All OK	Problems encountered	Operation
	Check that the engine temperature sensor is working correctly by carrying out the See Test 1056BC Engine coolant temperature sensor operation check	Move on to Step 7	Engine overheating	Restore the engine cooling system See E5020 ENGINE COOLING
		Move on to Step 7	Engine temperature sensor defective	Replace the engine temperature sensor Op. 1056B50 ENGINE COOLANT TEMPERATURE SENSOR - R + R
7	INJECTOR CHECK	All OK	Problems encountered	Operation
	Check that the injectors are operating correctly by carrying out Test_1056BA See Test 1056BA Injector operation check	Move on to Step 8	Injector stuck/incorrectly adjusted	Replace injector [PR_1056B70] Op. 1056B70 INJECTOR (ONE) - R + R WITH FUEL MANIFOLD PIPE REMOVED - INCLUDES SEAL REPLACEMNT
		Move on to Step 8	Connections not correct	Repair the connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
8	ACCELERATOR PEDAL CHECK	All OK	Problems encountered	Operation
	Check that the accelerator pedal is working correctly.	Move on to Step 9	Accelerator pedal potentiometer defective	Replace accelerator pedal [PR_1068A20] Op. 1068A20 ACCELERATOR PEDAL WITH BUILT-IN POTENTIOMETER - R.R
	Check that the accelerator pedal is working correctly.	Move on to Step 9	Connections not correct	Restore the correct connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
9	MOTORIZED THROTTLE OPERATION CHECK	All OK	Problems encountered	Operation
	Check the condition of the motorized throttle actuator connection Check the condition of the wiring Check that the motorized throttle is working properly, carrying out See Test 1056BW Check on the throttle body actuator operation	Move on to Step 10	Connection defective	Restore correct connection.
			Wiring defective	Restore the correct wiring.
			Motorized throttle defective	Replace the motorized throttle Op. 1056B14 THROTTLE CASE - R + R
10	CYLINDER COMPRESSION CHECK	All OK	Problems encountered	Operation
	Check that the cylinder compression is not too low Op. 0520G15 COMPRESSION TEST - CHECK WITH EXAMINER WITH SPARK PLUGS/INJECTORS REMOVED	Move on to Step 11	Compression too low	Overhaul the engine
11	ENGINE CONTROL UNIT OPERATION CHECK	All OK	Problems encountered	Operation
	Check that the engine control unit is working properly	End of diagnosis	Control unit defective.	Replace the engine management control unit Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R

1.9 JTD 8v, 1.9 JTD 16v

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 by doing the following: See Test 1040OA Fuel supply circuit check Check the operation of the low pressure supply circuit by carrying out the See Test 1060OB Low pressure fuel supply circuit check	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	MODE 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 PRESSURE CHECK · Engine rpm · Measured air mass · Engine coolant temperature See Test 5030AA COOLANT TEMPERATURE SENSOR CHECK	Move on to Step 2
2	ACTIVE DIAGNOSIS OF THE PREHEATING RELAY	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	GLOW HEATER PLUGS CHECK	All OK	Problems encountered	Operation
	Check that the glow heater plugs are working properly, by carrying out the See Test 5520CA GLOW HEATER PLUGS OPERATION CHECK	Move on to Step 4
4	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Carry out the active diagnosis for the E.G.R. solenoid	Move on to Step 5	Solenoid not working	Restore the wiring continuity See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the solenoid if necessary Op. 1080C24 E.G.R. SYSTEM SOLENOID - R + R
5	FUEL FILTER CHECK	All OK	Problems encountered	Operation
	Check that the fuel filter is working properly by doing the following: See T CHECK ON CHANGE IN PRESSURE AT THE FUEL FILTER	Move on to Step 6	The fuel filter is not working properly	Replace the diesel fuel filter Op. 1044B10 FUEL FILTER ASSEMBLY - R + R OR REPLACE
6	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 8	Cylinder compression insufficient	Move on to Step 7
7	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 the condition of the cylinders/piston rings	Move on to Step 8	Valve seal insufficient	Overhaul the cylinder head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
8	CORRECT OPERATION CHECK	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.R

1.4 16v TJet

The engine idle speed is not correct or the engine does not stick to the idle speed

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	First, check for: -leaks from the manifold gasket; -leaks from the throttle body; -leaks from the cylinder head.	Move on to Step 1	Leaks from the manifold gasket	Restore the correct gasket.
			Leaks from the throttle body gasket	Restore the correct gasket.
			Leaks from the cylinder head	Eliminate the leak
1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket and check: - that there are no errors in the engine management control unit; - parameter plausibility	Move on to Step 2	Error detected in the control unit	Continue following the instructions on the diagnostic equipment
		Move on to Step 2	Parameter not consistent	Continue following the instructions on the diagnostic equipment
2	PETROL VAPOUR RECOVERY SOLENOID CHECK	All OK	Problems encountered	Operation
	Carry out the active diagnosis of the solenoid valve	Move on to Step 4	Solenoid not working	Move on to Step 3
3	VAPOUR SOLENOID ELECTRICAL CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check the wiring between the valve and the engine compartment control unit Check the wiring between the valve and the control unit See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT	Move on to Step 4	Solenoid faulty	Replace the solenoid valve Op. 1080E28 ENABLEMENT SOLENOID FOR FLOW OF FUEL VAPOUR TO INLET - R+R
		Move on to Step 4	Connections not correct	Restore the correct connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
4	IGNITION SYSTEM CHECK	All OK	Problems encountered	Operation
	Inspect the spark plugs and check that they are working properly Check that the coils are working by carrying out See Test 5510CI IGNITION COIL OPERATION CHECK	Move on to Step 5	Spark plugs defective	Replace spark plugs Op. 5510D10 SPARK PLUGS - R+R
		Move on to Step 5	Coil defective	Replace coil Op. 5510C14 IGNITION COIL/S - R.R.
5	FUEL PRESSURE CHECK	All OK	Problems encountered	Operation
	Check the fuel supply pressure by performing the following: See Test 1056BI FUEL SYSTEM RETURN PRESSURE CHECK See Test 1056BY FUEL SYSTEM SUPPLY PRESSURE CHECK	Move on to Step 6	Fuel pressure too low: pipe obstructed	Eliminate the obstructions; if necessary, replace the pipe
		Move on to Step 6	Fuel pressure too low: pump defective	Replace the pump assembly Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
6	ENGINE COOLANT TEMPERATURE CHECK	All OK	Problems encountered	Operation
	Check that the engine temperature sensor is working correctly by carrying out the See Test 1056BC Engine coolant temperature sensor operation check	Move on to Step 7	Engine overheating	Restore the engine cooling system See E5020 ENGINE COOLING
		Move on to Step 7	Engine temperature sensor defective	Replace the engine temperature sensor Op. 1056B50 ENGINE COOLANT TEMPERATURE SENSOR - R + R
7	INJECTOR CHECK	All OK	Problems encountered	Operation
	Check that the injectors are operating correctly by carrying out See Test 1056BA Injector operation check	Move on to Step 8	Injector stuck/incorrectly adjusted	Replace the injector Op. 1056B70 INJECTOR (ONE) - R + R WITH FUEL MANIFOLD PIPE REMOVED - INCLUDES SEAL REPLACEMNT
		Move on to Step 8	Connections not correct	Restore the correct connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
8	ACCELERATOR PEDAL CHECK	All OK	Problems encountered	Operation
	Check that the accelerator pedal is working correctly.	Move on to Step 9	Accelerator pedal potentiometer defective	Replace the accelerator pedal Op. 1068A20 ACCELERATOR PEDAL WITH BUILT-IN POTENTIOMETER - R.R
	Check that the accelerator pedal is working correctly.	Move on to Step 9	Connections not correct	Restore the correct connections See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT
9	MOTORIZED THROTTLE OPERATION CHECK	All OK	Problems encountered	Operation
	Check the condition of the motorized throttle actuator connection Check the condition of the wiring Check that the motorized throttle is working properly, carrying out See Test 1056BW Check on the throttle body actuator operation	Move on to Step 10	Connection defective	Restore correct connection.
			Wiring defective	Restore the correct wiring.
			Motorized throttle defective	Replace the motorized throttle Op. 1056B14 THROTTLE CASE - R + R
10	CYLINDER COMPRESSION CHECK	All OK	Problems encountered	Operation
	Check that the cylinder compression is not too low Op. 0520G15 COMPRESSION TEST - CHECK WITH EXAMINER WITH SPARK PLUGS/INJECTORS REMOVED	Move on to Step 11	Compression too low	Overhaul the engine
11	ENGINE CONTROL UNIT OPERATION CHECK	All OK	Problems encountered	Operation
	Check that the engine control unit is working properly	End of diagnosis	Control unit defective.	Replace the engine management control unit Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R

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