22 · Diagnostics

Downstream lambda sensor signal error

Make: Alfa Romeo
Model: GT Factory Service Manual
Year: 2003–2010
Section: Examiner › Downstream lambda sensor signal error

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Fault diagnosisDownstream lambda sensor signal error

DOWNSTREAM LAMBDA SENSOR SIGNAL ERROR

3.2 V6

The diagnostic equipment signals the following error: Downstream Lambda signal

1.8 T.SPARK

The diagnostic equipment signals the following error: Downstream Lambda signal

3.2 V6

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Results of the tests
	Connect the diagnostic equipment (Examiner or Examiner Plus) and check the errors and environmental parameters. Check that there is only the downstream Lambda signal error	End of diagnosis	The upstream Lambda signal error is present	Continue as indicated in See table See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			The mixture strength error is present	Continue as indicated in See table See table Z50 MIXTURE STRENGTH ERROR
			The "misfire" error is present	Continue as indicated in See table See table Z53 MISFIRE ERROR
			The downstream Lambda signal only and/or catalyzer error are present	Move on to Step 1
			Other errors present	Identify and eliminate the cause of the problem. Move on to Step 8
1	ERROR DETAIL CHECK	All OK	Problems encountered	Operation
	Check the downstream Lambda signal error detail In particular, check that it is not invalid/below minimum level signal	Move on to Step 3	The detail is signal invalid/below minimum level with error P0136 and/or P0156	Move on to Step 2
2	INTAKE AND EXHAUST SYSTEM SEAL CHECK	All OK	Problems encountered	Operation
	Check the exhaust system by looking and listening. In particular, check that there are no leaks from the head outlet to the downstream Lambda sensor	Move on to Step 3	There are leaks	Restore the correct seal for the exhaust system, if necessary, replace the components involved
3	DOWNSTREAM LAMBDA SENSOR SWITCHING CHECK	All OK	Problems encountered	Operation
	Using the diagnostic equipment, cancel the errors in the control unit. Carry out a road test check and check the activation of the 2nd loop mixture strength using the diagnostic equipment	Move on to Step 4	The activation does not take place (or the signal does not switch)	Move on to Step 6
4	LAMBDA SENSOR WIRING CHECK	All OK	Problems encountered	Operation
	Check the downstream Lambda sensor wiring, checking that there are no false contacts See See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Move on to Step 5	There are false contacts	Restore the correct connections. If necessary, replace the defective components. Move on to Step 8
5	ECU SOFTWARE CHECK	All OK	Problems encountered	Operation
	Check for the existence of updated engine management software calibration	Move on to Step 8	There is no updated calibration for the control unit	Reprogramme the engine management control unit. Move on to Step 8
6	LAMBDA SENSOR/ECU INPUT WIRING CHECK	All OK	Problems encountered	Operation
	Check the wiring for the ECU downstream Lambda sensor input circuit, checking that there are no short circuits to earth, open circuits or false contacts See See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Move on to Step 7	There are faulty connections	Restore the correct connections. If necessary, replace the defective components. Move on to Step 8
7	DOWNSTREAM LAMBDA SENSOR REPLACEMENT	All OK	Problems encountered	Operation
	Replace the downstream Lambda sensor Op. 1080B60	Move on to Step 8
8	ERROR CANCELLING AND CHECK	All OK	Problems encountered	Operation
	Using the diagnostic equipment, cancel the errors in the control unit. Road test the vehicle and check that the errror does not occur again	Move on to Step 9	The fault persists, it is the first time that this Step has been reached and the Lambda sensor has not yet been replaced
		Move on to Step 9	The fault persists, but it is the second time that this Step has been reached or the Lambda sensor has already been replaced	Contact the Service Department for further information on the problem
9	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present	End of diagnosis

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