12 · Diagnostics

Diagnosis table

DiagnosisDiagnosis table · page 1 of 2

W02 Low CO emissions

A low percentage of CO is detected. NOx percentage is, however, higher than prescribed.

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 or B		All OK Go to Step 3	Problems found Faulty lambda sensor	Intervention Replace lambda sensor PROCEDURE OP. 1080B60
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3	CHECK AIR CIRCUIT Check – intactness and tightness of air delivery circuit		All OK Go to Step 4	Problems found Faulty circuit part	Intervention Replace part PROCEDURE 1048A
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4	CHECK FUEL PRESSURE Check fuel feed pressure PROCEDURE OP. 0510C10		All OK Go to Step 5	Problems found Incorrect pressure	Intervention Check circuit parts In the following sequence: – fuel filter PROCEDURE OP. 1044B10 – pressure regulator – fuel pipes PROCEDURE 1040 B
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