Hi All,

I've got a CL600 C215 from 2001 with the M137.970 engine.
I've been fixing a bunch of issues recently to get it back on the road.

However, I currently have an issue were it doesn't use the left bank of cylinders (7-12) at all. It's down on power, the exhaust is cold and I can see in the Autel that the O2 sensors, fuel injectors and camshaft sensor are all in a sort of off state. There are no DTC trouble codes in the computer at all. (well apart from a Distronic error). I've been struggling to work this out. The car behaves as if CSO (cylinder deactivation) is active and all is well in the world, like that's how it intended. No amount of throttle or changes to other inputs get the left bank to start.

Today a friend mentioned the right signal acquisition module that sits next to the ECU. I replaced this module with a used one from eBay because my fuse box was corroded to hell and some of the SAM pins also were. Everything else controlled by that SAM works well so I never thought to check if it needs coding. However I am now told that it does - although I got the identical part number (A0315451732), the software is specific to the car its installed into from new?

So here's the question, could a mismatched right SAM unit cause my left bank of cylinders not to fire?

I'm thinking that the ECU might be commanding that side on, but if the SAM came from a v8 say, that signal might to get to the left bank, and so the default state might be off rather than on? As far as I can see in WIS there are no dedicated fuses or relays for CSO in that fuse box. Only the ECU dedicated ones.

I can get it coded, but only at a MB stealer for the princely sum of £260 for the 30 minutes it will take, so I am reluctant to do that unless it could have a bearing on the engine.

I can't correlate the failure of the left bank to the SAM change or any other meaningful event purely in time, because the car was not being used. It's sat for 3 years and last time I parked it I had a bunch of errors, one being some misfire codes that I didn't want to get into 3 years ago.

 

If anyone finds this lonely post, I put an update here >> https://www.benzworld.org/threads/v1...ctive.3145155/
Basically the transformer was actually confirmed to be dead and I ordered a replacement Boost Box from v12icpack.com
Fingers crossed thats the only issue!

 

Update on my update. I am less sure now. Even though the Xentry test procedures say replace the transformer box, I have done that and there has been zero change. The car still only runs on the right side. Back to the drawing board.

 

Hey all, final update here.

I sent the ECU off to https://www.cartechelectronics.com/ who cloned my ECU onto a replacement one for a reasonable fee (they also accept returns minus a small fee in case that your ECU isn't the problem). Anyway I found that was the problem. As soon as I put the new one in I had error codes come up for the left bank that I could then follow to fix any remaining issues . ... the coil pack transformer box was faulty so I kept the Boost Box from https://www.v12icpack.com/ and I had to put a new O2 sensor on the left bank. All working well now.

I think I still have some moisture in my wiring harness, which is going to be a pain in the *** to sort, but other than that and some ball joints, it runs! And I have an MOT!

Thanks to everyone for your help with this.

 

I just found your thread; sorry for this lonely forum.

I've never heard of an ECU going bad, and it's a good thing you were able to diagnose it. Enjoy the car!

 

Thanks Fried Chicken, no worries, I got some help on a few other places to get to the end game. Water damage was the culprit. Not sure how. But sure UK weather over the last 2 years of it sitting outside was contributing.