Engine warning light - no message.

[Burger]

Don't know if these are related...

2007 SL350 (R230).

A few weeks ago I noticed the dash was displaying external temps much above reality (for example today it showed 18 degrees). Unfortunately my dad died the week before last and so I've had other things on my mind.

Today, while driving home, the engine warning light came on. No reduced power, no message, just the yellow engine warning light. I couldn't sense anything else wrong with the car. Of course it now stays illuminated each time I start the car.

I know I need to take it the dealers but I just wondered if anyone might have any suggestions on these faults... for example, does the wrong temp indicated suggest just the temp sensor is faulty or something more serious? Is there any way I can reset the engine warning light (understanding it might come back on) until I can get the car checked following dads funeral?

Many thanks.

 

[Pendragon]

Sorry to hear of your sad loss.
If its not causing you any problems then I would leave it as it is until after the funeral and then get a diagnostics test done on it to see what the problem is.


Keith

 

[Burger]

Thanks Keith, I agree. I've driven the car again today. It's starting 100% normally, running the same and I can't tell anything is wrong except for the light. I guess I'm just a little worried as the worst thing that could happen is it breaks down on the way to my dads funeral.

 

[clk208]

Sorry to hear of your loss.

A sudden appearance of the yellow engine light on mine (same engine as yours I think) shortly after purchase with no other symptoms turned out to be a duff cam sensor, a £20 part which didn't take long to fit, once the dealer decided to actually fit it instead of just resetting the fault code/clearing the light which is what they did the first 2 times I took it in.

In the meantime I was told it was fine to drive on an 800 mile trip I had lined up and got them to confirm this in email so you should be fine for a few weeks I would think.

 

[Burger]

Maidstone Mercedes were very helpful and booked the car in today for a while you wait slot. They had it all sorted in just under 2 hours. It turns out the faults were related. Apparently the ECU takes input from the external temperature sensor to assist with setting the right mixture. It also sort of 'double checks' it against other sensors and as Saturday evening was so cold it saw a difference it couldn't reconcile hence the engine management light.

The new part, an external temp sensor, was just £13.40 and they charged me that and an hours labour which seemed more than reasonable. All OK now