Engine Warning Light

sticker · 01-05-2023 8:03am #1

Hey all,

I've a 2015 Merc C300 Hybrid. The Engine warning light came on on Saturday while driving and I came stright home and parked it up. I did a quick search online and its not flashing which generally means its not a big issue. I'm stuck today obviosuly being a bank holiday with everywhere closed but I've the gym first thing tomorrow before I can book it into a garage.

Apologies for the vague questiion, but would it be safe to drive 10 minutes to the gym and back home or would best practice be to leave her alone and make the only trip be to the mechanic to plug it in and diagnose the error...

Thanks

User1998 · 01-05-2023 10:17am

Impossible to say without seeing the fault codes to be honest. But generally speaking it’s probably fine to drive. Most likely a sensor of some sort

bazz26 · 01-05-2023 11:18am

That's a generic warning light that could indicate any multitude of errors/problems. Normally a fault code is logged on the car's ECU that needs to be read by a garage with the correct diagnostic software. Amber light usually means that the warning or error needs to be looked by a garage, as said it could be a sensor. A red engine light would usually mean don't attempt to drive the car and get it looked at immediately.

sticker · 01-05-2023 11:46am

Many Thanks all. Much appreicated.

I'll run the risk then of driving in the morning and book her in first available spot.

Cheers!

sticker · 05-05-2023 8:56am

Just an update all - Got a local garage to do a quick diagnostic check (not my preferred one where I'm getting the work looked at on Monday)

Anyway - just a sensor but a Nox sensor I'm told and only Mercedes make them so could be up to €500.

At leaset its not anything serious...

Thanks again for the help.

User1998 · 05-05-2023 4:34pm

You’d get one from a scrapyard for about €100 I’d imagine

sticker · 06-05-2023 3:14pm

https://www.boards.ie/discussion/comment/120559631#Comment_120559631

Cheers, the garage I go to is a decent spot, I'm hoping they'll be able to source one like you suggest.

The Continental Op · 06-05-2023 3:20pm

With any sensor fault its worth double checking the wiring and connectors to the sensor before replacing it. The warning light tends to indicate a problem on a particular circuit but often can't tell the difference between a broken wire, a connector with corrosion or a failed sensor.

sticker · 07-05-2023 7:31am

https://www.boards.ie/discussion/comment/120562812#Comment_120562812

My garage has been great in the past, I assume they might check this first - Cheers for the heads up on it though. As a matter of interest, the other garage removed the warning light on the dash when they did the diagnostic, I hope my main garage will be able to see the error in 'history' - not sure how this works to be honest. Also, the warning light was zeroed a couple of days ago and I'm driving it regularly - would the error light not just pop up again if its still no resolved?

The Continental Op · 07-05-2023 8:23am

Did the first garage replace the warning light? Its not going to come back on if it isn't there anymore. But I doubt they removed the light.

The light is just a visual warning. There will be a history of any warnings on the cars "computer", the Electronic Control Unit ECU. That may have been wiped by the first garage but will be recorded again as soon as the error occurs. Somewhere on the car will be an ODB2 connection which the garage plug another computer into that can read any error codes stored on the ECU.

Its not that uncommon to have one off errors that don't come back. So if the light doesn't come on again the main garage can only read the errors stored on the ECU and its quite common for them to be wiped as a first course of action so the second garage may not see any errors.

ofcork · 07-05-2023 11:46am

The error code was cleared by the garage it will come back on in a few days probably until the sensor is replaced.

sticker · 08-05-2023 11:28am

https://www.boards.ie/discussion/comment/120564789#Comment_120564789

Sorry - meant to say they removed the warning light notice with the diagnostic hardware. The physcial light is still there on the dash, its just not highlighted. I've been driving for 3 days and if the error re-surfaced, it will come on again, It has not so far...

sticker · 08-05-2023 11:28am

https://www.boards.ie/discussion/comment/120565295#Comment_120565295

Yes, My garage have told me this. It still has not popped up again as yet...

sticker · 08-05-2023 8:49pm

https://www.boards.ie/discussion/comment/120565295#Comment_120565295

I would assume so too, but the error was zero'd last Friday and nothing back as yet...

barneygumble99 · 09-05-2023 6:31am

Diesel car I assume?? The nox sensor is a very common issue with them and there was a recall on them. I know the sensor is on backorder at the moment because the issue is so frequent. Might be worth checking with Mercedes if your car was due a recall or if it was ever done.