Undiagnosed ecu issue with hot engine no starts.
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Joined: Mar 2023
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From: Texas
Cls550
Undiagnosed ecu issue with hot engine no starts.
Hello all! Just trying to document my headache and hopefully help someone else with the same issue. By all means your input is greatly appreciated.
my 2007 cls550 104kmiles has been in a revolving mechanic door ever since I got a new manifold due to the well known flap issue. Shortly after I started getting random misfiring and a p0018. The car would start fine when cold, Drive for about 30 minutes or less once warm, then if I cut it off and come back (let’s say I’m running into the gas station) crank and no start. Let the car sit and cool down and she starts right up no problem until the same scenario. If I cut it off then crank immediately it will start. Had my Indy take a look and they said it’s either my flywheel or ecu to the price of a little over 4K. I didn’t like the “either” part of the diagnosis due to how my bank account is set up lol. Took it to Mercedes and they said they wanted to do my plugs and cam sensors. Ironically, my plugs were done 3k miles ago at the Indy. So I took her home and redid the plugs anyway along with the crank position sensor, camshaft magnets, camshaft sensors and still I have the hot start issue, no codes now.
I seen a YouTube video with a hot ecu causing no start and starting after the guy put the ecu in the fridge for a moment. So, I tried it…. Got the hot no start and I sat a bag of ice on the ecu for a few minutes and sure enough she started. Did it multiple times to be sure. Now I’m going to order a replacement ecu and see how that goes. Your thoughts?
my 2007 cls550 104kmiles has been in a revolving mechanic door ever since I got a new manifold due to the well known flap issue. Shortly after I started getting random misfiring and a p0018. The car would start fine when cold, Drive for about 30 minutes or less once warm, then if I cut it off and come back (let’s say I’m running into the gas station) crank and no start. Let the car sit and cool down and she starts right up no problem until the same scenario. If I cut it off then crank immediately it will start. Had my Indy take a look and they said it’s either my flywheel or ecu to the price of a little over 4K. I didn’t like the “either” part of the diagnosis due to how my bank account is set up lol. Took it to Mercedes and they said they wanted to do my plugs and cam sensors. Ironically, my plugs were done 3k miles ago at the Indy. So I took her home and redid the plugs anyway along with the crank position sensor, camshaft magnets, camshaft sensors and still I have the hot start issue, no codes now.
I seen a YouTube video with a hot ecu causing no start and starting after the guy put the ecu in the fridge for a moment. So, I tried it…. Got the hot no start and I sat a bag of ice on the ecu for a few minutes and sure enough she started. Did it multiple times to be sure. Now I’m going to order a replacement ecu and see how that goes. Your thoughts?
