22 · Diagnostics

Downstream lambda sensor signal error

Make: Fiat
Model: Doblò Factory Service Manual
Year: 2000–2010
Section: Examiner › Downstream lambda sensor signal error

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Fault diagnosisDownstream lambda sensor signal error

DOWNSTREAM LAMBDA SENSOR SIGNAL ERROR

The diagnostic equipment signals the following error: Downstream Lambda signal

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Connect the tester (Examiner or Examiner Plus) and transcribe the errors and environmental parameters Check for the 'Downstream Lambda signal' error only		'Upstream lambda probe' error present	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			'Mixture concentration' error present	See table Z50 MIXTURE STRENGTH ERROR
			The 'Misfire' error is present	See table Z53 MISFIRE ERROR
			The 'Downstream Lambda signal' and/or 'Catalyzer ' errors are present	Continue to Step 1
			Other errors present	Identify and eliminate the cause of the anomaly. Continue to Step 8
1	ERROR DETAIL CHECK	All OK	Problems met	Operation
	Check the detail of the 'Downstream Lambda signal' error In particular, check that it is not 'Open circuit or short circuit to earth'	Continue to Step 3	The detail is 'Open circuit or short circuit to earth'	Continue to Step 2
2	INTAKE AND EXHAUST SYSTEM LEAKAGE CHECK	All OK	Problems met	Operation
	Check the exhaust system, See Test 1072AIn particular, check that there are no leaks from the head outlet to the downstream Lambda sensor	Continue to Step 3	Leaks are present	Eliminate the leaks from the exhaust system, if necessary, replace the components involved
3	DOWNSTREAM LAMBDA SENSOR SWITCHING CHECK	All OK	Problems met	Operation
	Use a tester to cancel the errors in the control unit. Road test the vehicle and check the activation of the 2nd closed loop using the diagnostic equipment	Continue to Step 4	The activation does not take place (or the signal does not switch)	Continue to Step 6
4	LAMBDA SENSOR WIRING CHECK	All OK	Problems met	Operation
	Check the downstream Lambda sensor wiring, checking that there are no false contacts See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 5	There are false contacts	Restore correct connections. If necessary, replace the defective components Continue to Step 8
5	ECU SOFTWARE CHECK	All OK	Problems met	Operation
	Check that the engine management control unit software calibration is updated	Continue to Step 8	The control unit calibration is not updated	Reprogramme the engine management control unit. Continue to Step 8
6	LAMBDA SENSOR/ECU INPUT WIRING CHECK	All OK	Problems met	Operation
	Check the wiring for the downstream Lambda sensor input wiring in the ECU, checking that there are no short circuits to the supply or earth, open circuits or false contacts See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 7	There are faulty connections	Restore correct connections. If necessary, replace the defective components Continue to Step 8
7	REPLACING DOWNSTREAM LAMBDA SENSOR	All OK	Problems met	Operation
	Replace the downstream Lambda sensor Op. 1080B95	Continue to Step 8
8	DELETING AND CHECKING ERROR	All OK	Problems met	Operation
	Use a tester to cancel the errors in the control unit. Carry out a road test and ensure the error does not recur	Continue 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	Continue to Step 0
		Continue 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 Technical Support for further information on the problem
9	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists

The diagnostic equipment signals the following error: Downstream Lambda signal

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Connect the tester (Examiner or Examiner Plus) and transcribe the errors and environmental parameters Check for the 'Downstream Lambda signal' error only	End of diagnosis	'Upstream lambda probe' error present	Continue according to the instructions for the See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			'Mixture concentration' error present	Continue according to the instructions for the See table Z50 MIXTURE STRENGTH ERROR
			The 'Misfire' error is present	Continue according to the instructions for the See table Z53 MISFIRE ERROR
			The 'Downstream Lambda signal' and/or 'Catalyzer ' errors are present	Continue to Step 1
			Other errors present	Identify and eliminate the cause of the anomaly. Continue to Step 8
1	ERROR DETAIL CHECK	All OK	Problems met	Operation
	Check the detail of the 'Downstream Lambda signal' error In particular, check that it is not 'Open circuit or short circuit to earth'	Continue to Step 3	The detail is 'Open circuit or short circuit to earth'	Continue to Step 2
2	INTAKE AND EXHAUST SYSTEM LEAKAGE CHECK	All OK	Problems met	Operation
	Check the exhaust system visually and by listening In particular, check that there are no leaks from the head outlet to the downstream Lambda sensor	Continue to Step 3	Leaks are present	Eliminate the leaks from the exhaust system, if necessary, replace the components involved
3	DOWNSTREAM LAMBDA SENSOR SWITCHING CHECK	All OK	Problems met	Operation
	Use a tester to cancel the errors in the control unit. Road test the vehicle and check the activation of the 2nd closed loop using the diagnostic equipment	Continue to Step 4	The activation does not take place (or the signal does not switch)	Continue to Step 6
4	LAMBDA SENSOR WIRING CHECK	All OK	Problems met	Operation
	Check the downstream Lambda sensor wiring, checking that there are no false contacts See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 5	There are false contacts	Restore correct connections. If necessary, replace the defective components Continue to Step 8
5	ECU SOFTWARE CHECK	All OK	Problems met	Operation
	Check that the engine management control unit software calibration is updated	Continue to Step 8	The control unit calibration is not updated	Reprogramme the engine management control unit. Continue to Step 8
6	LAMBDA SENSOR/ECU INPUT WIRING CHECK	All OK	Problems met	Operation
	Check the wiring for the downstream Lambda sensor input wiring in the ECU, checking that there are no short circuits to the supply or earth, open circuits or false contacts See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 7	There are faulty connections	Restore correct connections. If necessary, replace the defective components Continue to Step 8
7	REPLACING DOWNSTREAM LAMBDA SENSOR	All OK	Problems met	Operation
	Replace the downstream Lambda sensor Op. 1080B60	Continue to Step 8
8	DELETING AND CHECKING ERROR	All OK	Problems met	Operation
	Use a tester to cancel the errors in the control unit. Carry out a road test and ensure the error does not recur	Continue 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	Continue to Step 0
		Continue 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 Technical Support for further information on the problem
9	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists

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