MTV10

Started up the car in the morning and within 5 seconds the fan was running full speed. It was 30+ degrees out so didn't think anything of it. Last night once it cooled down I noticed the same issue. Whether the AC is on or not the issue is present.

I've also noticed the coolant temperature reading is off. Showing 88 degrees and jumping down to 85 degrees and then back up to ~90 degrees.

I'm guessing my coolant temperature sensor has taken a dump. Has anybody else experienced this?

Found this thread and it mentions to replace sensor: https://mbworld.org/forums/c63-amg-w...ys-normal.html

Jasonoff

Probably the thermostat. Same symptoms when mine took a dump.

MTV10

Will this store a code?

Syed63

I experienced this issue new temp sensor resolved the problem.

Jasonoff

Yeah it did, it was 3 years ago so I don't remember the code. There's a few threads on it here though.

Sounds like it could be either that or the sensor if others have experienced the same symptoms with a faulty sensor.

MTV10

Where is this sensor located? Searched and searched and couldn't come up with anything.

Syed63

I took it to a speacilist who said there was a stored code pointing to the sensor. Because it wasn't expensive to replace I didn't go into it much with him. Just asked him to replace it without questioning

MTV10

Went in to visit Eurocharged this morning. They scanned the car and there were no codes whatsoever.

Was told to wait until this streak of hot weather passes to see if it continues. But as I stated in the OP.... this happens even at night when it's cool out and car has sat for 10+ hours....

MTV10

AC suddenly started blowing warm air this afternoon. Had it running full blast and was sweating bullets.

The plot thickens....

Jasonoff

It may be an open connection in the AC pressure sensor.

If you unplug the pressure sensor the AC fan will kick on full without a CEL. The pressure will read max value and there's apparently no code for too much pressure.

MTV10

Car spent the better part of the day at Eurocharged and came up with basically nothing.

The mechanic mentioned there is a sensor in the overhead console that is reading -182 degrees but I doubt that's the fix....

Not having AC on the hottest day of the year was not fun. Not to mention the fan blasting full speed any time I start the car.

zcct04

weather.com says its as hot in Montreal today as it is here in Houston - you guys must be dying! Hope you find a fix soon.

MTV10

UPDATE:

Brought the car in to MB Downtown and within 30 mins of the car going into the shop I got a call saying it was ready.

AC pressure sensor was reading 32 BAR . . . .

Jasonoff... you called it, sir.

Jasonoff

You'd think they'd have a CEL for high pressure.

So they evacuated your system, swapped the sensor, re-filled and you're good to go?

MTV10

Yeah man. Although I couldn't pick up the car before 6PM so it's sitting at the dealer. Drove by the dealership on my way home tonight and stopped in to check on the car. ...

Both front fenders are rolled outwards and pushed out. Whoever test drove my car did a number on my fenders... I'm losing it.