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Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit - Fixed #

Posted by Gerald Oliver on March 8, 2013, 7:08 pm

Year of Manufacture *: 2000
Engine Size and Code *: 1360cc
( Optional ) Scanner Used: Snap-on Solus pro
( Optional) Fault Codes: 42- 02 sensor circiut

We have a year 2000 Citroen Xsara with fault code 42-02 sensor circuit, this car has done 81000 miles, the customer has put a new cat on it, has had a NGK lambda sensor, also has put a new £15 coil pack on it.
The readings on the cryton gas analysis was
First fast idle test
co level 0.98% (Should be max 0.30%)
hc level 222ppm (Should be max 200ppm)
lambda 1.03 ( Should be 0.97 - 1.03
Second fast idle test
co level 1.00% (Should be max 0.30%)
hc level 248ppm (Should be max 200ppm)
lambda 1.02 (Should be 0.97 - 1.03)
Natural idle test
co level 0.74% (Should be max 0.50%)
Lambda sensor was working on live data.
Any help would be great.

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Mark Carter User icon on March 8, 2013, 8:13 pm, in reply to "Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"

What is live data telling you ?

What testing has been carried out with regard to the fault code?
Were the parts put on after testing or instead of?

Is the code still there after all the parts were fitted?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Pete Mutlow User icon on March 8, 2013, 9:31 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Peter Mutlow

Evening Gerald,

What make and what cost was the catalytic converter? Assuming the HO2 sensor is working correctly as you say, my bet is a cheap sub standard catalytic converter which is not up to the job.

Regards

Pete M

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Trevor Kelleher User icon on March 8, 2013, 11:11 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Trevor Kelleher

Ger can you read it through eobd?and get a proper p code description

That code you have is relating to a circuit fault,have you checked the o2 sensor voltage? plus circuits,ps,in my opinion i would be very slow fitting after market parts,
Ngk o2 sensors!!!
What make is the cat?

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by James Eardley User icon on March 9, 2013, 12:46 am, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"

I Would graph front and rear o2 activity in live data and road test

hth
James

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Mark Carter User icon on March 9, 2013, 1:53 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Mark Carter

>>> my bet is a cheap sub standard catalytic converter which is not up to the job.<<<

Surely not Pete, I thought we had standards and approval codes nowadays

Mark

Modern cars, Its all wizardry and witchcraft

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Gerald Oliver User icon on March 9, 2013, 3:31 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Gerald Oliver

The live data told us the Lambda sensor was working.
Emissions was tested on a crypton gas analysis.
The owner had a after market catalytic converter about 3 months before the mot, it is not a genuine citroen one.
Other parts fitted between mot fail and retest, they have also changed oil-plugs-air filter-petrol filter.

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Pete Mutlow User icon on March 9, 2013, 3:41 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"

Nice one one Mark. I would be very much interested in the answer to your question about the DTC still being present.

I have seen so many examples of this where a cheap catalytic converter has been fitted to a cheap car in the hope of getting the emissions down. Vehicles of this vintage regardless of mileage normally need a decent catalytic converter for any hope of a fighting chance to pass the MOT Exhaust Emissions Check.

Regards

Pete M

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Gerald Oliver User icon on March 9, 2013, 3:48 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Gerald Oliver

fault code is still there i forgot to post that in my last post.

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Pete Mutlow User icon on March 9, 2013, 4:05 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Peter Mutlow

Hi Gerald,

I am not familiar with the fault code that you have reported and I would go along with Trevor's suggestion and obtain a P code from the EOBD protocol.

Making the assumption that the Lambda sensor is switching correctly as you have suggested, it may have a fault with the heater circuit causing the MIL to illuminate.

Irrespective of that, my bet is still the
catalytic converter is not up to the job to get the emissions down to MOT standard.

Regards

Pete M

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by James Eardley User icon on March 9, 2013, 5:11 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"

Gerald

In my humble opinion

Your emission readings are quite typical of a failed CAT apart from
The CO readings 0.98/1.00, I would say are a little too high. I would expect to see around 0.60-0.70 if the vehicle was running correctly but the CAT had failed.

Hopefully someone will correct me if I am wrong with the above statement.

So you may have a failed CAT but due to another reason.

Addressing the fault code

As mentioned above check the heater circuit...
continuity test
is the ecu turning the heater on?
is there power to the heater circuit?
Check current flow through the circuit

You may have to load test all the o2 circuits

Has this got an after cat o2 sensor?
If so
Can you graph both sensors during a road test to check the efficiency of the CAT? or even just to eliminate the CAT from your enquiries.

HTH
James

Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #

Posted by Mark Carter User icon on March 9, 2013, 7:07 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"

Hi,

>>> The live data told us the Lambda sensor was working <<<

That's very good but what else did it tell you?

How is the load demand calculated / is the reading correct?

What does the rest of the data tell you?

>>> 42- 02 sensor circiut <<<

What is the engine code?

What engine management system is it fitted with, Marelli, Bosch or Sagem?

I assume either Marelli or Sagem as the fault code does not exist within the bosch fault code table. (both the others have a code 42 within their fault code table)

As has been said before what testing has been done, whats the resistance of the heater circuit of the sensor?

Is the supply good?

What current is flowing within the circuit?

Carry out some testing and we can help you pinpoint your issue.

Gut feeling is the heater circuit has been shagged for a while (do you know how long the MIL has been on for?) and the extended warm up phases (before closed loop control) have killed a marginal Cat.

But I wait for your results.

Mark

Modern cars, Its all wizardry and witchcraft

Fixed #

Posted by Gerald Oliver on March 17, 2013, 2:32 pm, in reply to "Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #"
Edited by board administrator March 21, 2013, 2:24 pm

we have fitted a new cat and everything is ok now.

Re: Fixed #

Posted by Mark Carter on March 17, 2013, 3:04 pm, in reply to "Re: Citroen Xsara 1.4 2000 - High emissions, code 42 o2 sensor circuit #FIXED"
Edited by board administrator March 21, 2013, 2:25 pm

So the Cat sorted the emissions, what about the fault code?

Just thinking that with a heater fault still there the new Cat will not last long.

Mark

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