The yellow engine warning light has come on. I topped up the oil as per advice, but it’s come on again.

What could it be?

S-max 2.0l petrol, 2014

Alert alert!

Impossible to say without a code reader mate

It could be a huge number of things, you’ll need to stick a code reader on it. Why’d you top up the oil, was it actually low?

I topped up the oil as per advice, but it’s come on again. What could it be?

An oil leak?

😉

lambda sensor in the exhaust? That’s what our peugeot usually has.
Oil warning is usually different warning sign.

Engine Warning Light
The Ford S-Max engine warning light means that the On Board Diagnostics system has detected a fault of the vehicle emission control system. If the engine light flashes, it means the engine may be misfiring which can result in damage to the catalytic converter. Avoid high speeds or high engine revolutions. The check engine warning light comes on due to many potential faults. In order to diagnose the fault, your S-Max will need to be connected to diagnostic equipment which can read stored fault codes.

Oil was low yeah.

It’s gone off now after I parked on a hill and had some chips

I just got the same light sorted in my car yesterday at its service. It was a glow plug seemingly but I have a diesel engine so no help to you

It’s gone off now after I parked on a hill and had some chips

Vision disturbance due to low blood sugar?

Keep eating chips.

I have a decent code reader, which I have leant to my father.
If you are in the Grantham/Sleaford/Bourne area you would be welcome to pop round and have a go with it. If you can show him how it works even better, it’s a bit tricky on the telephone🤣

I’ve got ForScan on my laptop, if you are near NG22

Just realised it’s you Pook, me and Ropey Reign Rider are trying to organise a Peak ride, I could bring it to you?

Ta, that might be good but I’ll see if I can find a garage tomorrow

Have you overfilled the oil?

You used to be able to get to a hidden menu on your dash to pull codes….

As these threads come up reasonably often, I thought i’d offer a bit more insight in to the ‘engine light’ to those interested (my credentials being I calibrate the logic in the ECU that determines whether the light comes on as part of my job).

The Malfunction Indicator Lamp (MIL) comes on – as noted in one of the posts above – when a fault has been detected that will degrade the vehicle emissions. The types of fault this could be are legislated as to at what fault level (how much more emissions than normal) the fault should come on and how often the ECU must check for a fault.

To set the MIL active, the ECU must detect the fault on 3 consecutive drive cycles (usually, sometimes some faults are 1 or 5 depending on severity) – a drive cycle being engine start to ignition off a d having passed some other parameters such as length of drive, average speed, etc. The logic uses a system of a pair of defect and healing counters. If a fault is detected the fault counter counts from 3 down to 1. If a fault isn’t detected it counts back up again, but at a slower rate; so for example it may need 3 drive cycles to set, but 5 to heal. If a fault is seen at least once then a code is stored in the ECU indicating what the detected fault was (but crucially NOT what the cause of the fault is) and this is what is seen when you use a scan tool.

There are fault codes that don’t set the MIL and these are for faults where the fault wouldn’t lead to an increase in emissions. These are there to help when you take your car in to the garage with an issue.

There are well over 100 different fault codes that could be set and some are legislated that they have to be there and others manufacturers add in to help diagnose issues – this is why sometimes a scan tool won’t show all fault codes; a generic one will just show the legislated codes whereas a manufacturer tool will show everything else as well.

So in answer to your question, it could be anything and should be taken to a garage (or checked yourself) to see what code has caused the MIL. Oil level is very unlikely as low oil level is not an emissions relevant fault – that’s why you have an oil pressure light as well. HOWEVER the fact there is low oil may be the cause of an emissions fault in some way so not to say they aren’t linked, but that you can’t draw conclusions from seeing the MIL and a symptom. And again, to reiterate, the fault codes only tell you the fault that was detected (e.g. a deviation between the expected and actual amount of air mass entering the engine) but not the cause of the issue (for that example it could be a stick EGR valve, or an air leak, or other issues) so be careful just looking at codes if you aren’t familiar with what might be the cause of a given fault.

That was long.

That was an excellent read. Thank you.

Oil level is very unlikely as low oil level is not an emissions relevant fault

Could high oil level not cause emissions issues though?

It’s for that kind of post that we need an ‘appreciated, thank you’ button.

@Speed12 Appreciated, thank you. BTW, is your name TVR related?

Could high oil level not cause emissions issues though?

It’s a good question – whilst it could, yes, I don’t believe it is OBD MIL relevant. I have to admit I might be wrong on that though (although I do some OBD calibration, it’s not my core area of work so I’m not a specialist on every monitor). The regs are very much about whether something is monitorable to give a quantifiable fault – although electronic level gauges are now much more common today, if the vehicle is a few years old it likely wouldn’t have one and so you have no way of properly knowing an overfill (oil pressure wouldn’t give an accurate indication) that would cause emissions to increase. Emissions also have to increase above a certain level to need to monitor it. The CO and HC levels – which an overfill may affect – are quite high and if you have a working oxidising catalyst you wouldn’t likely see a significant increase in tailpipe emissions.

BTW, is your name TVR related?

Haha, it is, but I don’t work for them 🙂 It’s a username I’ve had since I was at school and have just kept it.

I was thinking more at my neophyte level, a) I have half a memory that overfilling a modern engine is Bad and b) if there’s too much oil, where does it go? If it ends up in the chambers then, emissions issue.

But the last car I spent any serious amount of time under the bonnet of was a 91-plate so… 🤷‍♂️

Speed 10, orsum.

I like the cut of your jib.

Thanks.

Well it’s been a few days with no light now so I’m calming a bit

What’s the current oil level on the dipstick?

I’ll check in a bit when the engine’s cooled down.

If it’s like a VW code, yes, by all means buy a cheap code reader. This will then give you a code you can google which will translate as ‘could be anything’, regardless of the code. It will, or should at least be possible to clear the code and thus ignore it for a few weeks until your engine falls off.

2.0 petrol with Turbo? If it’s burning oil it could be a leaky manifold. Mine cracked and was putting oil into the turbo which eventually ruined it. Exhaust gas was also mixing with engine oil which wasn’t good for the bottom end which started knocking about 2 weeks later.

Get a reader on it and get it checked out or you could end up with a very big bill or a ruined car. Recon turbo was £350 + labour.