Engine Light On

[audrey]

Hi Guys hope you can help as it says above my engine light is on.Went on a while back and the guy in the garage said it was the o2 sensor.Well the 2 sensors have now been replaced and the light has come back on.Anyone know what this could be fed up going back and forward with this and getting nowhere.Hope you can help.Thanks in advance x

[audrey]

Anyone help please.....:frown:

[Gismo]

What guy in what garage? a main dealer would be able to rectify the problem by plugging in the code tool

[Craig]

yeah what he said ^^^

if they plug it in, they can normally work out what the problem is with the code machine. If both sensors have been replaced, it could be another faulty sensor, but to be honest, it's all guess work without the machine talking to your ECU. ;)

[audrey]

It was plugged into the code machine when light first came on and it came up the o2 sensors.Got these replaced and the light went out was plugged back into the machine and no further faults were showing.Light stayed off for couple of days then came back on.

[ELFMAN]

Audrey, my sensor light's been on for over a YEAR now! Had it checked out a while back and all emissions etc were within OK limits, and it's passed an M.O.T. too. I reckoned it was because I'm running a non-standard Manifold etc, but maybe the sensors are just rubbish. I've heard of this problem on other makes as well (SEAT etc). My car's running extremely well these days, so after I made sure I wasn't damaging anything (including the environment), I've learned to ignore it. While my car was under warranty, I was in and out of the Dealer a couple of times with this problem like yourself, and they cleaned or changed the sensor/s, but the light came back on again a while later.

These days I stick my wee Jimi Hendrix badge over it if the light's annoying me... very high-tech, you need just the right amount of Blu-Tack. If you're still 'Warrantied', you should probably pursue the Dealer for a solution, as it won't cost you - apart from the hassle of going back again.... and again....

[C.Noble]

If the original code was something like P0131, which officially means there is a low voltage coming from the oxygen sensor, most "technicians" will just read that code and say the sensor needs replaced. In reality what the ECU is actually saying is, over the last 50 or so miles, the reading I have seen from the oxygen sensor is too low, this can be caused by almost anything from a blocked/burst hose somewhere in the engine bay to a leaking exhaust (does it sound noisy?) if you just change the sensor without checking it properly (and that doesnt get done by a code reader by the way) and then just clear the fault code, it will keep the light out, making you think you have sorted it, but the cars brain tests it all the time, but wont tell you its failed, put the light on, until its finished its test, and that can take up to 100km (60miles).

What I am trying to get accross is, the light is on because the brain has seen something it doesnt trust, like or believe. Depending on the fault, the light MIGHT go out on its own, but that is unlikely and in any case it is unwise to ignore as it will most probably end up costing you money either on extra fuel or in an even bigger repair bill at some point.

There is no fancy computers/codes readers/scanners on the market that "fix" cars (if I ever see one I am buying all of them, they will be worth a fortune) only ones that can help properly trained people have a starting point in their diagnosis and assist them with the dreaded intermittant fault that never seems to happen within 200 miles of a workshop!

My advice is to get it checked by someone who knows what they are doing :Whistle:, and not someone with a glorified Gameboy and a set of spanners. Nothing hacks me off more than people getting ripped off, and giving us grunts a bad name. :ragin:

I will step off my soapbox now! :smilewinkgrin:

[audrey]

Audrey, my sensor light's been on for over a YEAR now! Had it checked out a while back and all emissions etc were within OK limits, and it's passed an M.O.T. too. I reckoned it was because I'm running a non-standard Manifold etc, but maybe the sensors are just rubbish. I've heard of this problem on other makes as well (SEAT etc). My car's running extremely well these days, so after I made sure I wasn't damaging anything (including the environment), I've learned to ignore it. While my car was under warranty, I was in and out of the Dealer a couple of times with this problem like yourself, and they cleaned or changed the sensor/s, but the light came back on again a while later.

These days I stick my wee Jimi Hendrix badge over it if the light's annoying me... very high-tech, you need just the right amount of Blu-Tack. If you're still 'Warrantied', you should probably pursue the Dealer for a solution, as it won't cost you - apart from the hassle of going back again.... and again....

Thanks Elfman car is still under warranty thats why still going back and forward as its not costing me anything.My car is also running well but gonna go back in next week when got time see if they can fix it this time.When warranty runs out will just try your badge thing sounds quite straightforard might even be able to manage it myself.:pThanks x:D

[audrey]

If the original code was something like P0131, which officially means there is a low voltage coming from the oxygen sensor, most "technicians" will just read that code and say the sensor needs replaced. In reality what the ECU is actually saying is, over the last 50 or so miles, the reading I have seen from the oxygen sensor is too low, this can be caused by almost anything from a blocked/burst hose somewhere in the engine bay to a leaking exhaust (does it sound noisy?) if you just change the sensor without checking it properly (and that doesnt get done by a code reader by the way) and then just clear the fault code, it will keep the light out, making you think you have sorted it, but the cars brain tests it all the time, but wont tell you its failed, put the light on, until its finished its test, and that can take up to 100km (60miles).

What I am trying to get accross is, the light is on because the brain has seen something it doesnt trust, like or believe. Depending on the fault, the light MIGHT go out on its own, but that is unlikely and in any case it is unwise to ignore as it will most probably end up costing you money either on extra fuel or in an even bigger repair bill at some point.

There is no fancy computers/codes readers/scanners on the market that "fix" cars (if I ever see one I am buying all of them, they will be worth a fortune) only ones that can help properly trained people have a starting point in their diagnosis and assist them with the dreaded intermittant fault that never seems to happen within 200 miles of a workshop!

My advice is to get it checked by someone who knows what they are doing :Whistle:, and not someone with a glorified Gameboy and a set of spanners. Nothing hacks me off more than people getting ripped off, and giving us grunts a bad name. :ragin:

I will step off my soapbox now! :smilewinkgrin:

Thanks for your advice beginning to think he doesnt know what hes talking about.Had a new exhaust fitted couple of months ago as it was rusty but i know this didnt cause the light to come on was on already.:frown:Anyway taking it back in next week to have the machine plugged into it again.Will let you know what he comes up with this time.Thanks again :D

[ELFMAN]

I've actually had the light go out of its own accord a couple of times. It'll then run for a while with no light and then 'Tinkerbell' will reappear and stay on. I was assured by the dealer (after testing - to whatever level they do it) that apart from a very slightly raised C.o. level (still within legal limits), there was nothing seriously amiss, so that's why I've left it. It cost me £45.00 to find that out. The fact that the car's been running with no problems for such a long time would seem to bear this out - although as has been said, there could be a whole range of reasons why the light's on, maybe mine is of the 'non-lethal' variety. My light was on and off before and fairly soon after I had my JCW 210 upgrade fitted. If your dealer can't get the light to go out and stay out, get it in writing that there's nothing else wrong, then at least you have some more 'comeback' (plus your warranty) if anything goes pop!

My light first appeared on the way back up from the Oxford Factory visit in 2006 (or 2007 - my memory's gone) and I had to radio for the guys to pull into the next Services to check it wasn't going to blow up. It's been mainly on and (very rarely) off since then - but still going fine.

[C.Noble]

It is possible for the light to be on for an almost insignificant reason, the tiny little heater circuit in the first of the two oxy sensor for example, this fault will only delay the operation of the oxy sensor by a few minutes after start up and is really unlikely in reality to affect the car or your wallet.

But, the whole point of the Malfunction Indication Lamp is to indicate a malfunction, therefore, you are likely to suffer from the old "cry wolf" trick, if you just ignore the reason the fault light is on, when another fault comes along, you wont know it... unless it breaksdown of course!

I would be VERY wary of anyone, ESPECIALLY a dealer, who tells you it is ok to ignore it because they cant find the cause, either they dont want to (cause they are underwriting the warranty) or they cant (then they shouldnt charge you for the repair/diagnosis).

I would also be VERY concerned about a slightly raised CO, most modern cars run nowhere near the MOT limits at idle, and if they do for prolonged periods, you can be sure the CATs life will be shortened, CO = partial combustion, which means the CAT is having to finish the job off in the exhaust, which means less bang for the buck (poorer/less good fuel economy) and a lower, albeit slight, power output.

My advice to anyone who puts a any car into a dealer or an independant garage for diagnosis in the event of a SRS, ABS, engine control, etc fault light coming on, would be to make sure they include the recorded fault codes in the final invoice, this will give you something to go on if the fault should return, and a google search will at least give you an insight into other peoples experience of the problem.

At the very least, I would always be happy to research and tell someone what there fault code means.

[ELFMAN]

Interesting.... I take on board what you're saying. My Car passed its M.O.T. this year with a Cat that's been on for at least 3 years. My fuel consumption's no worse (low 20's - 30's depending on my right foot) than any other 210 Works + bits, and the performance seems pretty good. If I'm not to trust the dealer's advice and how I feel the car's running (better than ever with its new ITG filter element) - what do you reckon I should do?

Should I get the dealer to run another Diagnostic and give me the fault code/s? That'd be another 45 quid for Dougie Park. Would the fact that I have a Playmini Manifold be affecting the gasses through the sensor which (presumeably) is set for the (tight as a duck's chuff) standard manifold etc? I know a couple of others have had this light problem after fitting aftermarket manifolds. Any advice gratefully received.

[C.Noble]

The manifold should not change the operation of the upstream oxy sensor, but depending on the design and the way the CAT is positioned between the two sensors may cause cat efficiency codes (P0420).

Without the reported code, I am afraid its all guesswork.

What I can suggest is if you are coming along to support Mr Dryden at the next meeting :thumbs up: at the Doune hillclimb on the 28th or the next Knockhill round on Oct the 19th, bring your MINI along and I will plug in and get the codes for you Free of charge (of course, if you are supporting a MINI from another team, I will have to charge you lots! :smilewinkgrin:), alternatively if you are passing through bonnie Fife anytime pm me and I will sort something out.

[audrey]

It is possible for the light to be on for an almost insignificant reason, the tiny little heater circuit in the first of the two oxy sensor for example, this fault will only delay the operation of the oxy sensor by a few minutes after start up and is really unlikely in reality to affect the car or your wallet.

But, the whole point of the Malfunction Indication Lamp is to indicate a malfunction, therefore, you are likely to suffer from the old "cry wolf" trick, if you just ignore the reason the fault light is on, when another fault comes along, you wont know it... unless it breaksdown of course!

I would be VERY wary of anyone, ESPECIALLY a dealer, who tells you it is ok to ignore it because they cant find the cause, either they dont want to (cause they are underwriting the warranty) or they cant (then they shouldnt charge you for the repair/diagnosis).

I would also be VERY concerned about a slightly raised CO, most modern cars run nowhere near the MOT limits at idle, and if they do for prolonged periods, you can be sure the CATs life will be shortened, CO = partial combustion, which means the CAT is having to finish the job off in the exhaust, which means less bang for the buck (poorer/less good fuel economy) and a lower, albeit slight, power output.

My advice to anyone who puts a any car into a dealer or an independant garage for diagnosis in the event of a SRS, ABS, engine control, etc fault light coming on, would be to make sure they include the recorded fault codes in the final invoice, this will give you something to go on if the fault should return, and a google search will at least give you an insight into other peoples experience of the problem.

At the very least, I would always be happy to research and tell someone what there fault code means.

Thanks for this bit worried about the CAT CONVERTOR sometimes especially going up steep hills it stinks is this normal or has that got anything to do with the light being on you probably think im stupid just not got a clue about anything mechanical:frown:Thanks for your advice x:thumbs up:

[ELFMAN]

The manifold should not change the operation of the upstream oxy sensor, but depending on the design and the way the CAT is positioned between the two sensors may cause cat efficiency codes (P0420).

Without the reported code, I am afraid its all guesswork.

What I can suggest is if you are coming along to support Mr Dryden at the next meeting :thumbs up: at the Doune hillclimb on the 28th or the next Knockhill round on Oct the 19th, bring your MINI along and I will plug in and get the codes for you Free of charge (of course, if you are supporting a MINI from another team, I will have to charge you lots! :smilewinkgrin:), alternatively if you are passing through bonnie Fife anytime pm me and I will sort something out.

VERY kind offer CN, I really appreciate that - I'll see what I can do. I'll send you a PM soon so we don't take over this thread! It'd be good to find out why I'm lit up, as I'd like to know if the wee motor's fully fit - it feels pretty good, but I might be missing something! :thumbs up:

[ELFMAN]

ps wouldn't DREAM of supporting another MINI than Mr. D's!

[C.Noble]

Thanks for this bit worried about the CAT CONVERTOR sometimes especially going up steep hills it stinks is this normal or has that got anything to do with the light being on you probably think im stupid just not got a clue about anything mechanical:frown:Thanks for your advice x:thumbs up:

It is not uncommon for the cat to stink a bit when you put the engine under high load (going uphill, overtaking, etc) its caused by the honeycomb inside releasing sulphur, hence the rotten egg smell, but depending on your driving style, it shouldnt last long.

If the fault light is on though, it is likely that the ECU has stopped listening to a sensor that it believes is faulty/incorrect and will substitute that information with a default figure, and as it is always safer for the engine to be slightly rich (too much fuel) than too weak (too little fuel) it will run a little more fuel than is required and this can cause a smell on high load.

[mikeythemini]

There are some very bad aftermarket sensors about so I always use genuine parts.
A fault I have seen on Minis is the wire from the llamda sensor rubbing on the heat shield & shorting out, bringing on the light

[audrey]

Thanks for all your replies :thumbs up:Elfman hope you get your light problem fixed post it up and let me know :smilewinkgrin:

[audrey]

There are some very bad aftermarket sensors about so I always use genuine parts.
A fault I have seen on Minis is the wire from the llamda sensor rubbing on the heat shield & shorting out, bringing on the light

Gonna check that its the genuine sensors hes put on my car.Maybe this could be the problem cheap parts trying to save money.Will speak to him next week when i go in.:thumbs up:

[ELFMAN]

As far as I know, all my sensors are original BMW parts. Audrey - I'll keep you posted!

[C.Noble]

Thanks for all your replies :thumbs up:Elfman hope you get your light problem fixed post it up and let me know :smilewinkgrin:

I dont know if you are into the racing too, or if you are likely to be passing through Fife, but if you are, give me a shout, I can do a quick code read on your MINI too if you want.

[audrey]

Never been to the racing :frown: Fife is quite a drive away from me but thanks for the kind offer and taking the time to give me advice been really helpful much appreciated.:D

[audrey]

CN The fault code was p0131.Put the car in yesterday for a service.Same code came up again but as the sensors have both been replaced he had an electrician take a look at it.The light is off for fingers crossed it stays that way.Anyway the electrician said it was something to do with a wire causing high resistance.Does this sound right to you?Every time I turn the engine on keep expecting to see the light come back on :frown:

[C.Noble]

oops! missed this post today...:blush:

P0131 is a fault code relating to the Oxygen sensor, as are all codes starting p013x and relates to the first of the 2 sensors (before the cat) this particular code means for at least 40 seconds continuously, the sensor indicated a VERY weak air/fuel mixture or for 10 seconds continuously a weak air/fuel mixture, when this is detected, it should put the fault light on, and keep it on until it sees 4 "drive cycles" (that is 4 runs that start from cold and last long enough to reach normal operating temp) without fault, if it experiences the fault again within those 4 cycles, the counter is reset, and the light is left on.

In simple terms, if your light has been on for a week, and you use the car at least twice a day for at least 7-8 miles each time and the light has never gone off, that would suggest the ecu sees the fault at least once every two to three days, but this time can be longer if the car does nothing for a few days or the runs are too short.
If, now that your code has been erased, the fault light does not come on within the next two weeks, then the fault probably was caused by one of your old sensors.

But, if the light does come back on, then obviously they were not at fault, but at the very least, that is one possible cause probably ticked off.

P0131 basically means there is too much oxygen at the first oxygen sensor for too long, this can be caused by;

an exhaust leak around the sensor or the exhaust manifold gasket.
This would normally, but not always be audible to the driver, particlarly under full load.

Not enough fuel being delivered (blocked injectors/low fuel pressure,etc)
This would usually be apparent to the driver as a drop in performance, again especially under high load, although, if you are not guilty of driving like you stole it, you might never notice.

An air leak in the induction side
Unless REALLY bad, the driver probably wont notice this, but sometimes it will manifest in a bad/lumpy/high idle.

Faulty MAP (Manifold Absolute Pressure) sensor
this little sensor tells the ECU how much pressure there is in the inlet system, and is pretty much a direct indication of the load the engine is under, and therefore how much air is being consumed, if it is incorrect/lying, then the air/fuel ratio will be incorrect, and therefore the light will come on. As above, this may not be apparent to the driver, but may affect the idle.

I hope this helps... and that I havent bored the $%*$ off you all!

Lesson for today over :idea:... next week, how to build a MINI race car in 7 days... then how to REBUILD a MINI race car in 6.

[Craig]

VERY interesting info there Craig - thanks for that. :thumbs up:

[Burple]

Yip, Craig... what Craig says...
Top info! :cool:

(Arg!.. too.. many... Craigs... head... imploding!! :laugh::laugh::thud:)

[audrey]

Thanks for this Craig :smilewinkgrin:Really helpful hopefully the light will stay off this time keep you posted.At least I know now what these sensors are for.Anyway gonna go now you must be sick of all my questions :p