You'll need to read the codes, it can mean pretty much anything.

It's useful to have your own cheap obd reader so you can search for the codes yourself and have a rough idea of what the garage is going to say/charge before you go to them.

Or if it's minor thing fix yourself.

 

I'm thinking it has to be a sensor of some kind, as it drives fine.

 

I'm thinking it has to be a sensor of some kind, as it drives fine.

I don't know about the mk3 but my MK2 did that and it was the fuel pressure sensor. My Mrs st had the same sensor fail, but hers sometimes had boost issues as well +fuelling issues if you looked at the data. I've seen a few people say same as you and it turned out to be the same sensor.

Mk3 could be something different, and I have seen a few other problems with the same (or lack of) symptoms so could easily not be the fuel pressure sensor.

Unfortunately even assuming it's a sensor you've got probably a couple thousand £££ worth of sensors it could be so you need to read the code throwing the light to get an idea.

Or I could just tell you it's the fuel pressure sensor and it may or may not fix your light, depending how much you trust a stranger on the internet

 

I'll let you know, it's going back to garage 👍

 

A simple USB type OBD2 reader, assuming you have a laptop or tablet, will be a lot cheaper than trips to the garage.

Even if it's something you don't want to "fix" yourself, at least you will know if the garage is giving you an honest opinion and not just charging you for un-necessary work.

 

Same thing happened to me. But it was the fuel that I had just put in that was the cause. Never been back to a bp petrol station since. Lol

 

No point in guessing, the answer is to get your own reader and check the code.

As a starting point though, you can ask your garage what code came up when they first checked it.

It's very unlikely they "updated" your PCM, much more likely they just read and reset the code.

 

Yeah, I've ordered a reader. I was a bit dubious that all they did was update it. Fully expected it to come back on. Had similar issue on my old Mini, which turned out to be O2 sensor

 

Had it checked and garage have said the error was that the engine was running too cool. Anyone seen that? So it's clear again and no extra charge. They let it sit and thermostat opened, then fans kicked in, so it all looks good. Have to see how it goes I guess? I've bought a reader for future testing.

 

That's quite uncommon.

Was the temperature gauge reading low?

 

Not that I noticed, just below the middle of the gauge. Do they do through a learning process after an upgrade?