TCU tune done, car will not start
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Joined: Aug 2013
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From: Anchorage
05 CL65
TCU tune done, car will not start
Sent my TCU off for a tune February 24. Thought it would only take about a week or two for the TCU tune but just got it back yesterday. I disconnected the battery before removing it and had no intention of hooking it back up until the TCU was reinstalled, but given the long wait I decided to replace my passenger seat occupancy sensor while the car was parked waiting on the TCU. To do the seat I had to hook up the battery and turn the key to ACC so I could move the seat. The only code I had before removing the TCU was the occupancy sensor and the car ran and started every time without issue. Now I have a bunch of codes and the car will not turn over.
Current codes I am concerned about are:
B1040 - fault in CAN communication with control unit ME motor electronics
C1022-025. CAN communication with the engine system is faulty
Also the dash is saying instrument cluster display defective and ESP fault in addition to the SRS warning I already had.
Also a few other codes for sunroof not normalized, safety time exceeded for muliticontour backrest, trunk lid angle. I think theses are related to having the seat out and the trunk open for a month but none of these should prevent the car from starting.
Battery is fully charged and has been on a tender so not a voltage issue. Could removing the ECU and TCU as well as lifting out the fuse box between them have caused this issue? I have already double checked the plug ins to the ECU & TCU & they are plugged in correctly. Fuses in that fuse box are all good, have not looked elsewhere yet.
Any suggestions on where to start trying to find the CAN communication error?
Not sure where to even start with so much showing up all at once.
Current codes I am concerned about are:
B1040 - fault in CAN communication with control unit ME motor electronics
C1022-025. CAN communication with the engine system is faulty
Also the dash is saying instrument cluster display defective and ESP fault in addition to the SRS warning I already had.
Also a few other codes for sunroof not normalized, safety time exceeded for muliticontour backrest, trunk lid angle. I think theses are related to having the seat out and the trunk open for a month but none of these should prevent the car from starting.
Battery is fully charged and has been on a tender so not a voltage issue. Could removing the ECU and TCU as well as lifting out the fuse box between them have caused this issue? I have already double checked the plug ins to the ECU & TCU & they are plugged in correctly. Fuses in that fuse box are all good, have not looked elsewhere yet.
Any suggestions on where to start trying to find the CAN communication error?
Not sure where to even start with so much showing up all at once.
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From: South FL & NYC
Your worst nightmare...
Did you disconnect the ECU? If you did you may have not connected right. Please recheck your connections. If I recall there is one wire which connects to the ESP control unit from the ECU, I may be wrong. Either ways sounds like a connection problem.
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From: Chicago
W215 V12TT Build by Speedriven, W221 S550 4Matic
Disconnect everything and slowly start from step 1 and before you install anything check everything over 5 times. You should be all good.
Thread Starter
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Joined: Aug 2013
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From: Anchorage
05 CL65
Yes I did unplug the ECU. I was told the TCU is located under the passenger carpet at first, then it was "under" the ECU. After looking in both the locations it wasn't I decided to stop listening to people who "know" where it is and opened up my STAR to research & find out for myself.
At least pulling the carpet up wasn't a total waste as I wired in my dual dash cam to the main power wire from the battery going to the relay under there while I had it up. That way the dash cam will be on 24/7 unless I turn it off so it will function as a security cam also. Just need to remember to turn it off when I pull in the garage if I'm not driving the car every day.
I'll pull it back out and recheck everything tomorrow. Hate to admit it but I pushed the CL outside to work on building the wall for 2 Fi 18's in my sons Chrysler 300. Told him we would build his sub box as soon as my TCU got back.......didn't expect that to be this long.
At least pulling the carpet up wasn't a total waste as I wired in my dual dash cam to the main power wire from the battery going to the relay under there while I had it up. That way the dash cam will be on 24/7 unless I turn it off so it will function as a security cam also. Just need to remember to turn it off when I pull in the garage if I'm not driving the car every day.
I'll pull it back out and recheck everything tomorrow. Hate to admit it but I pushed the CL outside to work on building the wall for 2 Fi 18's in my sons Chrysler 300. Told him we would build his sub box as soon as my TCU got back.......didn't expect that to be this long.
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Thread Starter
MBWorld Fanatic!
Joined: Aug 2013
Posts: 1,077
Likes: 80
From: Anchorage
05 CL65
One of the cam locking wire bundles to the ECU did not catch and therefore was not making a connection. Simple fix at least! 
. Now if I just had a replacement ribbed idler pulley I could be driving my CL again....... Been parked since the original idler failed over a month ago. Marcin help!
On an even better note I just ordered a set of Niche Essen wheels to replace the EM2's that don't fit over my rear brakes
Now if someone would come out with a 275/35-19 drag radial.....
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MBWorld Fanatic!
Joined: Mar 2009
Posts: 2,630
Likes: 9
From: Chicago
W215 V12TT Build by Speedriven, W221 S550 4Matic
One of the cam locking wire bundles to the ECU did not catch and therefore was not making a connection. Simple fix at least! . Now if I just had a replacement ribbed idler pulley I could be driving my CL again....... Been parked since the original idler failed over a month ago. Marcin help!
On an even better note I just ordered a set of Niche Essen wheels to replace the EM2's that don't fit over my rear brakes
Now if someone would come out with a 275/35-19 drag radial.....
Thread Starter
MBWorld Fanatic!
Joined: Aug 2013
Posts: 1,077
Likes: 80
From: Anchorage
05 CL65
Yes a 305/35-19. Just not sure I can tuck that much tire. Will have to see once the rims arrive. I think I'll be able to run them but they are 28" tall and it will require a custom offset. I think I can get the right offset by having a pair of 8.5's widened 1.5" to 10".
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,768
Likes: 5
From: South FL & NYC
Your worst nightmare...
One of the cam locking wire bundles to the ECU did not catch and therefore was not making a connection. Simple fix at least! . Now if I just had a replacement ribbed idler pulley I could be driving my CL again....... Been parked since the original idler failed over a month ago. Marcin help!
On an even better note I just ordered a set of Niche Essen wheels to replace the EM2's that don't fit over my rear brakes
Now if someone would come out with a 275/35-19 drag radial.....
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From: In my garage
E55, GLS450, GL63, GLE350
Don't think so. The only ones I've seen running 305's were on 20" wheels. I tried on a 10 x 19" wheels and the tires where hitting the strut and sticking out an inch past the fender. It may be that the tires buldge when on a smaller diameter wheels. Not really sure but it didn't come close to fitting on my car.
Thread Starter
MBWorld Fanatic!
Joined: Aug 2013
Posts: 1,077
Likes: 80
From: Anchorage
05 CL65
Well if that's the case I may be running mismatched rims at the track. I'll find out as a buddy has some 295/35-19's so I'm going to mount one up once the wheel get here and that should give me a good idea of the fit of a 305.
