12 · Diagnostics

Diagnosis table

DiagnosisDiagnosis table · page 1 of 2

Percentage of CO and/or HC higher than prescribed.

NOTE: Check preliminarily:
- air cleaner conditions

Step	Validity	Operation to be performed	Test results
Step	Validity	Operation to be performed	OK	⚠
1	CHECK WITH DIAGNOSTIC TOOL	Connect diagnostic tool (Examiner or other tool) to the diagnostic socket. Check: - no fault in engine ECU - plausibility of all parameters	All OK Go to Step 2	Problems found Intervention
			All OK Go to Step 2	Detected error in ECU	Continue as shown by the diagnostic tool
			Failed dialogue with ECU	Restore connection between engine ECU and diagnostic socket (Wiring diagram: E5030 "PETROL ENGINE ELECTRONIC MANAGEMENT")
2	CHECK LAMBDA SENSOR	Check correct operation of lambda sensor TESTS 1080B test A	All OK Go to Step 3	Problems found Intervention
2	CHECK LAMBDA SENSOR		All OK Go to Step 3	Faulty lambda sensor	Replace lambda sensor PROCEDURE OP. 1080B60
3	CHECK CATALYTIC CONVERTER	Check correct operation of catalytic converter operation	All OK Go to Step 4	Problems found Intervention
3	CHECK CATALYTIC CONVERTER	Check correct operation of catalytic converter operation	All OK Go to Step 4	Faulty catalytic converter	Replace catalytic converter PROCEDURE OP. 1080B62
4	CHECK AIR CIRCUIT	Check - intactness and tightness of air delivery circuit - correct assembly of air cleaner	All OK Go to Step 5	Problems found Intervention
			All OK Go to Step 5	Damaged circuit part	Replace part PROCEDURE 1048A
			Incorrect air cleaner assembly	Restore correct air cleaner assembly PROCEDURE OP. 1048A14

(Cont..)

Parts & tools for this job For 1998 Fiat Seicento

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