Bad start when engine is warm
Thread Starter
Newbie
Joined: Nov 2010
Posts: 7
Likes: 1
06, ML500
Bad start when engine is warm
My 2006 ML500 starts badly when the engine is warm (mainly when driving to local stores and making several stops). Had this issue since 2010 but it got bad this year. A couple of days ago I have replaced Crankshaft Positioning sensor but the problem didn't go away so it's something else. I do not have check engine light nor any other warnings when the car has this issue. Whatever is happening it is not sending any codes to a computer. I am thinking that it might be a bad starter or maybe a bad ground connection (which gets hot after engine warms up)? I am not sure how to test this theory. I also had my battery replaced a while back and I still had this issue. I have uploaded two videos which show this issue (watch both it's from the same start and please turn your speakers up to hear starter turning)
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
Likes: 765
From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Yes it sounds like a starter issue or a starter related issue.
Proceed as follows with the key out of ignition:
Go to Eng. Comp. Fuse/Relay Box #F58 and locate & remove Starter Relay KI. Rough up each of the 5 blades, on both sides, with sandpaper. Insert and remove relay a number of times and then attempt to start eng.
If the problem is not resolved, perform the same above procedure with fuse 105, 118 & 122 in that order but do them individually and try eng. start.
Newbie
Joined: Jan 2019
Posts: 2
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ML500
No start when engine is warm - CPS and Starter Motor
I had this same problem over the Christmas holiday. The car would start fine when the engine was cold - like first thing in the morning. After running errands the car, at first, would randomly not start, with the same symptoms you report. It got worse, to the point where the car would not start at all when warm or hot. I took it to the dealer 5 days ago and just got it back, they replaced the Crankshaft Position Sensor (CPS), which was bad, but the starter motor also was on its last legs, would randomly fail to engage. Replaced both, just picked up the car today and the problem is completely resolved. My 2006 ML500 has 210K miles and this is the first Start Motor replacement, which I consider to be quite acceptable.
