It's been quite hot this week (upper 90s) and I've noticed my bluetec has been idling around 800-900 RPM. At a light it creeps forward pretty fast, it usually idles around 550-600rpm. Has anyone else experienced this?

 

The idle is raised when the outside temperature is above 87 degrees and the A/C is engaged. Turn off the A/C when this happens and watch the idle return to normal. It seems to be working as designed.

 

Mine has the same symptom every so often when it's going through a regen cycle. Sometimes they seem to take forever, as in notice it, drive 20mi on the highway and it's still going when I get home.

I do love the 5500rpm idle. Our 2009 ML320 always seems to be idling at like 7000+ plus and don't notice the regen at all. I assume that's to spec but never really compared it against another?

 

Yep, very consistent like you stated.

 

This is normal and by design.

 

Yup, this morning it hit 87 and like clockwork the idle went up to 800. Pressed the A/C button and it stayed at 800... but cold air continued to come from the vents. When I turned the entire system off the idle then dropped.

 

I purchased a CPO 2011 E350 bluetec in November 2013. Now that our Florida weather is warming up, I have noticed the same thing. The car has been back to Benz three times and twice they applied software updates, this time to the screen module. Less than two hundred miles later, it is doing it again. Funny thing is, I don't think it is a regency issue as I don't smell the fumes or hear the metallic crackling as the exhaust system cools down.MB has said nothing about the rpm raising up when the account is on yet, frequently turning off the account and giving the car two quick revs brings the girls back down from 700 to 550. The only time it doesnt seem to drop the rpm is when the car is in a real regency cycle. How come Benz doesn't have a clue?

 

Meant to type SCR MODULE, not screen module.

 

The increased RPM is to facilitate transmission cooling at idle. There was a TSB several years ago on the behavior.

 

Thank you. Would you know where to find the link? Also, was the TSB to just advise me techs as to why the idle speed increases in higher temps?

 

high idle more command during high temperatures. I have a e350 2011 bluetec v6, 120,000 miles but today after 60 days of normal ideling at 68 degrees the emgine idled at 800 rpms.I turned the engine off and back on and the idle drops to 600.when coming to a red light I lower the transmission to neutral when the idle is 800, it still keeps running at 800. I know the extra pressure on the transmission can not be good.
Made appointment with dealer, they have no clue.
Now what do I do?..

 

stop to worry and read the manual.
Your car has DPF who runs regeneration process every few hundred miles. That raise rpm when happens

 

Hi all, I got same issue with my ml350 bluetec, did you had the chance to fix the high rpm problem? If yes, what did you do? Thanks

 

Did youi get a reply? Mine is idling at 800 rpm 600 with the air off