2006 Jetta Manual Swap / Mechatronics Unit replacement

[0micca]

Hey guys-

I'm new to VWs, I picked up a 220k mile Jetta with an intermittent p1746 code. From what I've seen, it's a solenoid circuit malfunction typical of a failing Mechatronic unit.
So now I'm weighing my options.
1. Manual swap
2. Brand new Mechatronic (I believe part number 02E-325-025-AT-Z5W, would appreciate a double-check on this)
3. Used mechatronic unit gamble
I'm a mobile mechanic, and I'd like to use this car for jobs not requiring my full toolkit. My 7.3 IDI truck gets 13-14mpg and diesel ain't cheap these days.
So my questions-
What manual transmission codes should I look for? I'm confused by generation overlap, speed sensors, and gear ratios...
Is $1200 for a new mechatronic unit reasonable?
Will the ECU be upset by a manual swap? What programming would be required? I have a decent Launch scanner, it seems to be pretty good at talking to these cars.

 

[moonshyne0986]

Replacing the mech would be much less of a headache. Swapping out to a manual has a lot more to do inside the cabin and under the hood. With the Audi clutch pack on the DSG you'll never have another problem with it. At least I haven't since I did mine. I have a 2006 Jetta that I bought with the flashing PRNDS code and installed the mech and programmed it and I had never worked on one at the time. I then had Jeff install a , 150hp turbo, PD150 injectors with Bosic PP1043+10% nozzles, 3bar map, Franks cam, and get 38 to 40mpg on this cheap Indiana diesel. The DSG will shift faster than you ever can and in normal mode is smooth as glass bud. I have had so many trucks and cars with manual trans. After daily work commute on interstates you'll get tired of shifting gears.

 

[oilhammer]

I'd rather row my own gears.

Last I checked, the M-unit for BRM cars was NLA. But they may have become available again. There are two different letter code 02Es for the BRM, so two different M-units possible.

Nobody here rebuilds them, and the ones that do in Europe seem to have an awful reputation. There are some aftermarket parts available, I have no experience with them myself. I've replaced a LOT of M-units with new ones, though. They seem to get really bad in the 2012-17 range, for some reason.

 

[Matt-98AHU]

Like Oilhammer said, the BRM mech units seem to be unobtanium these days.

As for manual swap options, the 02S 6 speed is a great one. You can use the more commonly available and cheaper 5 speed parts, but still have an extra gear. The TKR and TDZ code 02S family boxes we got in 2019-2024 for the 1.4 and 1.5 TSI engines are geared perfectly for old 1.9 TDIs.

So, if you did find a Mk5 5 speed manual swap parts, you can make it a 6 speed quite easily.

Or, if you do want to go a little taller geared (and more expensive clutch and flywheel), yes, you can use the 02Q 6 speed from one of the commonrails and of course have to use all the 6 speed specific parts to go with it (axles, starter, clutch hydraulics, shift linkage etc).

The 02S TKR/TDZ will have you spinning about 2275 RPM @ 80. I think the TDI 02Q 6 speeds are more like 2125 RPM at the same speed in 6th.

 

[tactdi]

Or, if you do want to go a little taller geared (and more expensive clutch and flywheel), yes, you can use the 02Q 6 speed from one of the commonrails and of course have to use all the 6 speed specific parts to go with it (axles, starter, clutch hydraulics, shift linkage etc).

That is what i did, the 02Q 6 speed swap when my 5 speed broke. Been working well, the 02Q and maybe the other 6 speeds use the internal
slave cylinder in the bell housing. The first slave lasted a couple of years, before it started leaking, had to pull the trans to replace it.
Replaced it (could have been a metal one), with the OEM Plastic one, which has been holding up for 5 years or so.

 

[0micca]

I'd rather row my own gears.

Last I checked, the M-unit for BRM cars was NLA. But they may have become available again. There are two different letter code 02Es for the BRM, so two different M-units possible.

Nobody here rebuilds them, and the ones that do in Europe seem to have an awful reputation. There are some aftermarket parts available, I have no experience with them myself. I've replaced a LOT of M-units with new ones, though. They seem to get really bad in the 2012-17 range, for some reason.

Damn... where do I see which 02E transmission I have? I'll see if I can order a mechatronic unit. I would honestly rather just fix the auto if I could get another 100k miles out of it. Also, say I got a new m-unit and installed it. Do I need someone with a vagcom to make the ECU play nice with it? I don't have one, and I can't justify buying one. I don't work on many VWs.
I'll manual swap if I really need to.

 

[oilhammer]

Or your local dealer can decipher by VIN. And yes, you'll need an appropriate scan tool to get it to work.

 

[Matt-98AHU]

That is what i did, the 02Q 6 speed swap when my 5 speed broke. Been working well, the 02Q and maybe the other 6 speeds use the internal
slave cylinder in the bell housing. The first slave lasted a couple of years, before it started leaking, had to pull the trans to replace it.
Replaced it (could have been a metal one), with the OEM Plastic one, which has been holding up for 5 years or so.

That slave cylinder issue is exactly why I like the 02S 6 speed so much. Heh

So very rarely see failures with the 5 speed slave cylinder, and if it does fail, it's just two bolts on the top of the transmission. Transmission removal not required. Not to mention, the transmission is not as wide and weighs quite a bit less. Makes it easier to remove and reinstall without pulling the sub-frame.

The clutches and flywheels are also cheaper... And the synchros aren't as sensitive to being swapped to a single mass flywheel like the 02Qs are.

Sure, the 02Q is technically stronger, but they seem to be more problematic and expensive than the MQ250 architecture.

 

[oilhammer]

Supposedly the later 02Q has a lot of improvements over the earlier ones... some of which came post-Dieselgate, so we'll never get to enjoy them.

Seems the R prompted some need for extra strengthening, which pushed it through to other lesser cars.

 

[0micca]

Factory options sticker, located in the trunk, and another copy in the owner's manual. Look for Engine/Trans code. It'll be the 3-letter code next to BRM.

Thanks, it's the HXU.

Or your local dealer can decipher by VIN. And yes, you'll need an appropriate scan tool to get it to work.

Wonder if my launch tool can do it. Do you know what function I need to access? This tool is usually pretty good with euro cars.

 

[oilhammer]

No idea. Our shop had one of those for a hot minute, it was pretty abysmal.

You have to go into Basic Settings, and go through all the 3-digit numbers to do everything. VCDS is the only way I know how to do it.

 

[0micca]

No idea. Our shop had one of those for a hot minute, it was pretty abysmal.

You have to go into Basic Settings, and go through all the 3-digit numbers to do everything. VCDS is the only way I know how to do it.

Oh okay, looks like I do have access to that under "special functions".
Gonna try to source a mechatronic unit now.

 

[spietro84]

@0micca - Were you able to source a mechatronic unit? I'm the same situation as you with P0868 & P1815 codes.

If you did can you provide a source?

 

[backfast61]

Ordered one a few years ago from the dealership
Just need the VIN. Paid around $1200. I “ guess “
they are still available.