22 · Diagnostics

CO EMISSIONS LOW, NOx EMISSIONS HIGH

Make: Fiat
Model: Multipla Factory Service Manual
Year: 1998–2010
Section: Emissions › CO EMISSIONS LOW, NOx EMISSIONS HIGH

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Fault diagnosisCO EMISSIONS LOW, NOx EMISSIONS HIGH

CO EMISSIONS LOW, NOx EMISSIONS HIGH

1.6 16v

The CO percentage measured is very low, with a corresponding NOx percentage which is much higher than recommended.

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check the condition of the air filter Check the condition and seal of the air supply circuit	Continue to Step 1	Filter element dirty or damaged	Replace the filter element Op. 1048A14
		Continue to Step 1	Circuit component damaged	Replace the component (see Assembly 1048A)
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 fault in the engine management 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 engine management control unit and the diagnostic connector ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT).
2	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other iinstruments) carry out the active diagnosis of the iinjectors.	Continue to Step 3	Connections faulty	Restore the connection of the solenoid valve with the control unit ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT).
		Continue to Step 3	Injectors faulty	Replace the injectors Op. 1056B70
3	LAMBDA SENSOR CHECK	All OK	Problems met	Operation
	Check that the Lambda sensor is working properly	Continue to Step 4	Lambda sensor not working properly	Replace the Lambda sensor Op. 1080B60
4	BLOW-BY CIRCUIT CHECK	All OK	Problems met	Operation
	Check the condition of the blow-by gases intake circuit. In particular, check that there are no obstructions in the separator or in the pipes	Continue to Step 5	Blow-by circuit faulty	Restore the correct operation of the circuit: if necessary, replace the pipes (see Assembly 1080D)
		Continue to Step 5	Fault in the separator	Replace the separator Op. 1080D34
5	FUEL PRESSURE CHECK	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 6	Pressure not correct	Replace the fuel pump assembly Op. 1040A70
6	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'

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Parts & tools for this job For 1998 Fiat Multipla

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