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.....

[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 , 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.

I will step off my soapbox now!

[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.Thanks x

[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 , 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.

I will step off my soapbox now!

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.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

[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.