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BMW 325 2.5 1994 - Oxygen sensor fault - Fixed #

Posted by Piotr Sokolowski on November 14, 2010, 12:39 pm

Year of Manufacture *: 1994
Engine Size and Code *: 2500
( Optional ) ECU Type: bosch
( Optional ) Scanner Used: solus pro
( Optional) Fault Codes: o2 sensor circuit

Hello if I ask you because I feel lost with tjis one. My brother in law car. Haven't spend much time o0n it but. He brought the car with o2 sensor circuit , sensor is still on 0.48V.So we decided to replacxe the sensor -ok.After r4eplacement still the same. Checked by tester and on the sensor by scope. Add earth on the grey wire still the same. Any ideas?
Car has got lpg instalation fitted.

Link: www.pandpauto.eu

Re: bmw 325 oxygenn sensor fault

Posted by kevin gregory User icon on November 14, 2010, 2:09 pm, in reply to "bmw 325 oxygenn sensor fault"
Kevin Gregory

does the sensor respond to wide open throtle blip when running on petrol.what are the exhaust gas readings when on petrol.what is the fault code you are getting.after clearing the fault do you have to drive the car to get fault back or is it there on start up.

Re: bmw 325 oxygenn sensor fault

Posted by Piotr Sokolowski User icon on November 14, 2010, 2:30 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

there is no response for a WOT at all.Because it's brother in law he was working on it own and I just was giving him a hand. I will do some more tests on saturday and I will post them .Thanks

Link: www.pandpauto.eu

Re: bmw 325 oxygenn sensor fault

Posted by Mark Robins User icon on November 14, 2010, 4:42 pm, in reply to "Re: bmw 325 oxygenn sensor fault"
Mark Robins

With LPG fitted doesn't the LPG ECU dummy the O2 sensor in the same way the injectors are??

Just a thought

Mark

Re: bmw 325 oxygenn sensor fault

Posted by lee woods User icon on November 14, 2010, 6:43 pm, in reply to "Re: bmw 325 oxygenn sensor fault"
Lee Woods

Piotr has the wiring to the lamdas got any other wiring cut into it from the gas ecm , i guess the lamdas are not switching when running on petrol .

Re: bmw 325 oxygenn sensor fault

Posted by Mark Carter User icon on November 14, 2010, 7:59 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

Hi Piotr,
disconnect the sensor harness from the loom and Look at the voltage displayed in live data.What is it?

Now bridge the two sensor wires in the loom end of the connector with KOEO.

What voltage is displayed in live data?

What fault codes are logged?

Let us know.

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: bmw 325 oxygenn sensor fault

Posted by Piotr Sokolowski User icon on November 14, 2010, 8:43 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

I definitely will let you know. Mark as far as I remember you are not in on tuesday and wednesday in Exeter?

Link: www.pandpauto.eu

Re: bmw 325 oxygenn sensor fault

Posted by Andrew West User icon on November 14, 2010, 10:11 pm, in reply to "Re: bmw 325 oxygenn sensor fault"
Andrew West

Hello Piotr,
Tell your brother to look for two wires cut into the lambda cicuit, usually one being grey & another purple from the lpg ecu(depending on system). Most lpg systems have the ability to wire into the lambda circuit for diagnostic purposes & does not effect the running on lpg, but can alter the signal going back to the petrol ecu, so that fuel trims don't change(by simulating a signal). If the lpg system is set up/calibrated correctly, then there is no need to connect the wires so that the signal circuit to the petrol ecu is broken, but it is sometimes usefull to tee in the purple wire to get a lambda reading on the lpg software(but more accurate viewing fuel trim data on a scan tool). I have quite often found installations where the signal wire has been spliced into, but the signal sheild wire has also been spliced at the same time. Sometimes I have found that the pins have been pulled out of the connector plug where the loom has been pulled to wire in the lpg systems wire.There could also be a fault with the feedback voltage from the lpg ecu, so in this case if the signal wire is joined back as original , it should sort it.
Hope this helps, regards, Andrew

Re: bmw 325 oxygenn sensor fault

Posted by Piotr Sokolowski User icon on November 14, 2010, 10:33 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

many thanks for advises as I said will check it on saturday .The weird thing for me is 0.48v by scantool and 0.48v on the sensor using scope.

Link: www.pandpauto.eu

Re: bmw 325 oxygenn sensor fault

Posted by aidan User icon on November 15, 2010, 8:05 am, in reply to "Re: bmw 325 oxygenn sensor fault"
Aidan Birley

Piotr

If it has a current O2 sensor fault code, I would think that .48 v could be a ECU default / substitute value.

Cheers Aidan

Re: bmw 325 oxygenn sensor fault

Posted by Mark carter User icon on November 15, 2010, 8:55 am, in reply to "Re: bmw 325 oxygenn sensor fault"
Mark Carter

Hi Piotr, no, I am not delivering the scope course in Exeter, I am on holiday from mid week onwards so a colleague of mine is running the course.

The voltage you are seeing should be the reference voltage from the ECU to the sensor.

If there is any non OE wiring in the circuit then disconnect that first.

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: bmw 325 oxygenn sensor fault

Posted by Piotr Sokolowski User icon on November 15, 2010, 6:48 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

yes there is a wiring for the lpg ecu. I don't know how it is works.So I don't think I will be able to help him. I did try but how you can know the answer if you don't know how the system (lpg) works .Regards guys.

Link: www.pandpauto.eu

Fixed #

Posted by Piotr Sokolowski on November 20, 2010, 7:00 pm, in reply to "Re: bmw 325 oxygenn sensor fault"

hello I went with your advise guys- cut the wire from lpg ecu into the oxygen sensor and lambada sensor started working .Thanks for your input guys

Link: www.pandpauto.eu

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