Kar don

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?

HBerman

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.

Mbenz260e

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?

thekurgan

Yep, very consistent like you stated.

ImInPA

This is normal and by design.

Kar don

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.

tdisedanman

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?

tdisedanman

Meant to type SCR MODULE, not screen module.

HBerman

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

tdisedanman

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?

Oseberg

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?..

kajtek1

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

Liro

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