[mercysakesalive]

I'm getting ready to pull the trigger on a used a TCM on Ebay for $200 with a return policy available. I'll let you know how it turns out when I get it in the first week of January. Thank you! Also I found someone that can recode it -- though it is done by shipping both the old and new TCM of state.

 

[the big e]

That’s great!
I would wait a bit on the recode for a bit to make sure it doesn’t have to be returned.
Hopefully it doesn’t give any trouble and you can then send both off for the recode.
Keep us posted.

 

[mercysakesalive]

I got the new used TCM and installed it. I got 3 bars on my dashboard so I'm assuming this is a faulty TCM. There aren't any other TCM's with the same # as mine on Ebay. Where else should I look to find a used TCM?

 

[jwight]

Did you try the transmission relearn procedure?

 

[the big e]

Yeah I forgot to mention that.
Do that and and see if it works afterwards.
I had to do it on my blue 08 when i swapped its tcm out.
Don’t start the car just turn the key to run and hold the brake then work it through the gears(it may not have to be done but it’s worked for others) you’ll hear the clutch actuator and shifter motors for a bit then it should show the p in the cluster screen.
Otherwise there is another issue that’s causing it(mine was both tcm and clutch actuator)

 

[mercysakesalive]

Im confused. Jwight asks if i tried the transmission relearn procedure and posts a video of an xentry procedure... but thenbig E says "yes try that" and describes a procedure that doesn't use xentry. Can you clarify what i should be doing?

 

[the big e]

Ok there’s two ways of doing it.
One involves the scan tool to force it into doing the relearn the other will make it do it on its own.

I did the later as at the time I didn’t have access to the scan tool.
If the one I described doesn’t work then yes you’ll need the scan tool.
Sorry for the confusion.

 

[mercysakesalive]

Ok thanks for clarifying. So if the non-xentry procedure does NOT work then its still possible i have a good TCM that just needs the Xentry hooked up for the relearn procedure? ... EDIT : the relearn worked so disregard this comment.

 

[mercysakesalive]

Holy wow, the transmission relearn worked! Ok now to troubleshoot and see if the new TCM makes the problem go away. Its an intermittent issue so it may take a bit of time...

 

[the big e]

Yep as you’ve seen it can be done both ways.
Hopefully it fixes the issue.
Given it was a voltage issue from the tcm it shouldn’t unless this one is bad too.(it shouldn’t be)

 

[jwight]

Holy wow, the transmission relearn worked! Ok now to troubleshoot and see if the new TCM makes the problem go away. Its an intermittent issue so it may take a bit of time...

Good to hear!

 

[mercysakesalive]

So far so good. Question: the new TCM is not recoded to my VIN but it seems to work fine. I'm leaning toward NOT recoding it... is there any reason that not recoding it is a bad idea?

 

[vadsoom]

Here’s the procedure if anyone looks through this thread in the future…


If you get three bars on your instrument cluster, try this:

• Step on the brake
• Turn the key to the “on” position, but don’t start the car.
• Slowly cycle through the gears, pausing at each position. You should hear the shift motor and clutch actuator moving.
• Slowly cycle back through the gears to Park.
• Take your foot off the brake
• Turn the key off
• I’ve heard that locking and unlocking the doors at this step is necessary , but I’m not convinced. You can try it anyway.
• Wait a few moments.
• Restart the car. The clutch should function again. Some have reported disconnecting the battery for 20 minutes helps.

 

[mercysakesalive]

Yes, everything that Vadsoom said about reteaching a transmission when you get the 3 bars was true for me except I did not have to lock and unlock the doors. Also, I ran a diagnostic after I did the reteaching and I got a P0949 code "ASM adaptive learning not done". I drove the car around for 2 miles and the code went away. So maybe the transmission learning involves driving for a couple miles.... besides that, so far the new TCM seems like it has fixed the no-starting problem, though I won't be confident that its fixed until maybe midweek at the soonest.

 

[mercysakesalive]

Day 2 of using the new used TCM unit and everything continues to work correctly. I'm no longer getting the P0886 code that was associated with the intermittent no-starting issue.

Strange though-- prior to swapping out the TCM, I was getting another unrelated code that told me one of my tire pressure sensors had stopped working. But now with the new TCM, I no longer get that code... head scratcher.

Is there any reason I should have this TCM coded to my VIN? Is there any potential runnability issues if I just leave it uncoded?

 

[the big e]

That’s odd it was doing that but it could be interference who knows.(other than that it would be the battery in the sensor)

ive had mine in my blue 08 for a little over a year and no issue with it(it was November 14th 2021 when I swapped it out) but I had to swap out the fuel pump due to it being dead but no issues aside from the vin mismatch code.
It’s worked flawlessly since.
Can’t believe it’s been two years since I got it running.

 

[mercysakesalive]

Ok so you never recoded your new TCM ? Did i understand that correctly? Maybe i won't bother for now.

 

[the big e]

Nope you read that right.
No rush to get it done.

 

[mercysakesalive]

I hope I'm not popping the cork on the champagne too soon, but I've put the new used TCM under test for 3 days now and have not had any codes nor had any starting issues. I think the car is more than likely fixed. Thank you to Vadsoom for giving me the troubleshooting help to pinpoint the TCM and eliminate the SAM and the clutch actuator from the culprits. Thank you to the Big E for your advice on buying a used TCM and pointing out that I didn't need to recode it. And thanks to Jwight for jumping in at the last minute with the transmission control reteach advise. All in all, I spent $220 on a used TCM. I think if I had gone with a new TCM and had the mercedes dealership install and recode it, it would have cost ~$1200. Thanks again everyone!

 

[the big e]

That’s awesome!
Your welcome.
The price is correct btw I know from experience.