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· Registered
366 Posts
Discussion Starter · #1 ·
Does anyone have a Mopar Performance SRT TCM, p/n P5155177, on an 09 Challenger SRT?

I bought one in February. It performed no different than a stock TCM. Stock shifts, and the Hold In Gear feature did not work. The car still up-shifted automatically in Autostick.

So, I returned it and they ordered another one for me. Same thing! No difference from stock and no Hold In Gear.

So I contacted the Mopar Direct Connection Tech Line. The Tech said they've had no problems with this MTCM. We talked. I shipped this MTCM to him and asked him to install it in an 09 Challenger SRT and see what happens. He did. He said that the MTCM that I sent him works as advertised on that car! Hold In Gear and all! His engineers tested it and also said it was working fine.

"What now?" I asked. He didn't have an answer for me. He said I am the first person that has ever said that the P5155177 MTCM didn't work.

He said, "It must be your car."
"My car is bone stock. How can it be my car? Is there an update that I need?"
"No. It always works."
"So, who can I call to troubleshoot this?"
"No one."

In a nutshell, there's something about my car that this MTCM won't work with, and. . . , too bad.

Has anyone else installed this and had it not work? All I want is the Hold In Gear feature.

This MTCM is advertised to work on 2005-2009 6.1's (as printed on the instruction sheet).

· 392 Inertia Stroker
4,073 Posts
Some cars have been known not to take the MTCM in the 5.7 crowd. It can be a hit or miss deal, talk to AJ Hemituner he may be able to help you out!

· Registered
366 Posts
Discussion Starter · #3 ·
I want to update this in case anyone reads it in the future.

I got it to work!

I tried 3 of these TCM's. None of them gave me the Hold in-Gear that it is designed to do. Like some other people that had the same problem, I connected my Predator, tried a few different settings over many days, and the Hold in-Gear finally started to work!

I don't know if one of the Transmission Modes I tried finally did it, or if it was more a matter of the Predator's tune being under control for a period of time. I'm leaning towards the latter.

After a few days of having Hold in-Gear, I installed the original tune and unmarried the Predator. I still have Hold in-Gear!

After a few days of making sure that didn't change, I re-connected the Predator and installed a Performance tune. I still have Hold in-Gear.

It looks like connecting the Predator "sets" something in the TCM's memory.

Why this TCM doesn't work like it's supposed to in certain cars-I don't know.
Why connecting the Predator fixes it-I don't know.
The fact that it stays set after I unmarry the Predator-gives me confidence that it is now permanently set.

The only thing I have not done to see if it remains set, is disconnect the battery.

I hope that helps someone in the future.
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