2015 RS5 - Gearbox Malfunction

[dubai_rs5]

Hi,

Had a complete loss of drive in my 2015 RS5 yesterday at motorway speed, accompanied by the TPMS and Gearbox Malfunction message. I pulled over and restarted the car and managed to get it driving again but only gears 2, 4 and 6 were working. Started it again this morning and was driving completely fine again, and the TPSM and gearbox malfunction had gone. The engine warning light was still showing but that disappeared after driving around for a while and restarting again. Recently I’d noticed the downshift from second to first was a bit clunky when coming to a stop in automatic mode, but not bad enough to worry me. The car nearly 60k kms /38k miles and is due a major service including all transmission fluids and S-Tronic oil.

Any thoughts what the issue could be?

Many thanks!

[rnp614]

Have you ever changed the battery?

[dubai_rs5]

Yes about 2 months ago

[Ape Factory]

First, I'd get a VCDS cable and scan for codes. Second, did you get to the point where your battery failed and you had to change it or did you change it prior to it completely failing? Did they code the new battery in? You're over the recommended mileage for the service though so it could be a fluid issue (worn, improper level).

[JamesRS5]

I have VCDS if you want to read the codes, where are you staying?

You lost one side of the gearbox, I'd definitely have the service done on the gearboxes, they are very sensitive to fluid levels/changes.

[dubai_rs5]

Audi have inspected it and have advised it needs a complete gearbox replacement costing USD 20k! The service engineer doesn’t have great English and can’t give me any more detail other than “problems with mechatronic, gear selector and synchroniser”. I’m planning to call into the service centre and see the diagnostic report, but replacing the whole gearbox seems overkill and I think Audi are just being lazy.

James - really appreciate the offer. I think I’ll drop it into Autohaus for the service and to see if they can propose a repair option, but I might call over to you for a second opinion depending on what they say...

[Ape Factory]

Yep, that's insane. Someone is taking the easy route and not doing their due diligence. The mechatronic itself can be rebuilt and depending on what the fault is, it could be down to the PCB board going bad. There's an upgraded PCB Audi sells separately. The gear selector can be one of two things, one is internal on the "gear" side of the transmission, one is on the mechatronic side, the PCB. The synchronizer, I'm a little lost on that one. The actual gearbox itself is super stout. So I think it's probably related to the gear selector forks being out of spec but probably due to another issue (mechatronic, solenoid or PCB). Fixable in other words, without replacing the entire gearbox. But listen to James, he's not only local but knows his stuff.

[JamesRS5]

Dubai Audi don't employ any skilled labor, they need to call in the flying doctor if they have any issues other than routine. If I remember correctly you still have an extended warranty? If so then they are simply abusing the system in getting the highest assembly on the parts list that doesn't involve them wasting time stripping down gearboxes but that shouldn't make any difference to you if you are covered.

Deutsche Technik: https://dtservicecentre.com/?utm_sou...medium=organic

These guys are pretty good with Audi diagnosis, lots of R8s outside in various states of repair, my friend just had his misfiring S3 diagnosed there.


I would certainly have it serviced first just to make sure it's not the basics.

[dubai_rs5]

Thought I would update on the issue. I brought the car to Autohaus in Dubai (reputable indy shop) who refurbed the mechatronic unit including replacement of some sensors, solenoids and repair to the circuit board. They also did a major service on the car (38k miles / 60k kms) which included replacement of all transmission fluids and filter.

The car seemed fine initially but after a few days has developed a very harsh jerking when coasting to a stop as the transmission changes from second to first. The car is also hesitant when pulling away in first in both D and M modes, usually followed by a harsh jerk before the car begins to accelerate normally again. It almost feels like the car is misjudging the biting point on the clutch when pulling away and not engaging it sufficiently, before dumping after a second or two which causes the shunting sensation.

The gearbox is shifting normally above second gear - the issue is only at low speed when pulling away or coming to a halt.

Any idea what the issue could be?

Many thanks.

[Ape Factory]

Improper installation/adaptation is one idea, if the solenoids get replaced they need to code the mechatronic in again. The other possibility is it could have been the pressure regulator valve which can cause symptoms like that. If they didn't replace then internal clutch thermostat and pressure regulator valve, they may have replaced components that didn't need replacing. They have to test the valve body to see which chambers are holding pressure and which aren't. But I'd take a hard look at the pressure regulator valve to see if it's holding pressure. If it isn't the bore may be worn. You can get the Sonnax oversized valve and have the shop ream it (if they have the proper tools) to install the larger valve and all will be good.
https://www.sonnax.com/parts/4281-ov...ator-valve-kit

Heat lowers the viscosity of the fluid which is already quite thin. This can cause wear in the solenoids and bores. You can go with a slightly thicker fluid but that doesn't shed heat as readily. A good cooler is the best solution. Try switching to Liqui-Moly 8100 too. Seems to be a great fluid.

[dubai_rs5]

Ape Factory - thanks, very helpful. The fault codes when the problem initially happened were:

P17D4 - Valve 3 in partial transmission 1 mechanical malfunction. N435

P1776 Hydraulic pressure sensor 1 adaptation limit reached. G193.

From what I can tell, N435 is the solenoid that operates the clutch and G193 is the pressure regulator valve you’re referring to?

My gut feeling (could be wrong) is that the clutches aren’t engaging smoothly - too little pressure initially followed by a sudden increase in pressure causing the clutch to “dump” and sending a bang through the drivetrain.

[dubai_rs5]

Quick update - they’ve run the diagnostics and only the P174D code is showing. So looks like it’s a faulty solenoid? Or is it possible that the underlying problem is with the hydraulic pressure inside the unit and this is causing the solenoid sensor to trigger?

[Ape Factory]

It's most likely the solenoid going bad which is triggering the second code. There's usually a main code, in this case, P174D, but there should also be a second "symptom" code associated with P174D. See if you can find that info. A lot of times the main code is caused by another component going bad which can trigger another code. Hence the P174D combined with P1776D. Doesn't mean the pressure sensor is bad (P1776D), it's just seeing an out of range pressure, possibly due to a solenoid going bad (N435 or maybe N436).

-N433 controls shift fork for gears 1-3
-N434 controls shift fork for gears 7-5
-N435 clutch control solenoid clutch pack 1
-N436 controls pressure for the clutch 1 pack (odd gears)
-N437 controls 2nd gear and reverse
-N438 controls the shift fork mechanism, gears 4-6
-N439 Clutch control solenoid clutch pack 2
-N440 for the clutch 2 pack, pressure regulator (even gears)
-N471 is for cooler flow, clutch pack cooling
-N472 is the main pressure control solenoid

-G193 isn't a solenoid, it's a pressure sensor on the TCU but inside the mechatronic, guessing it measures pressure for clutch pack1
-G194 is the pressure sensor for clutch pack 2

Resistance for each solenoid
N433 5 Ohms
N434 5 Ohms
N435 15 Ohms
N436 5Ohms
N437 5 Ohms
N438 5 Ohms
N439 15 Ohms
N440 5Ohms
N471 4.5 Ohms
N472 4.5 Ohms

They should also check for wear as the bores can become ovalized and it doesn't hold pressure when the transmission gets hot.

[dubai_rs5]

Thanks Ape Factory, sounds like you know these boxes pretty well! Which pressure control valve should I check for wear? The clutch pack regulator (N436/N440) or the main pressure control valve (N472)?

[JamesRS5]

Did Autohaus run the Basic Settings procedure after their repairs? Assuming they use VCDS on their computer then ask them to run the following:

http://wiki.ross-tech.com/wiki/index...rbox_(DSG/0B5)

[hahnmgh63]

I'm thinking with your miles the bores are fine but probably is the Solenoid. But as JamesRS5 and Ape said, check to see if the shop ran the adaption, it is important to run it per the manual.

[Ape Factory]

Agree with the above although something has gone wrong despite the low miles. If the PCB circuit board/plug is replaced, no adaptation needed. But if they replaced any solenoids, the computer needs to know what position it's in and it's range as it'll be all new vs. the old. Otherwise it's going by how the old solenoid was "clocked" which would lead to drivability problems.

A bit off topic but something I've been thinking about for a while. N437 controls both reverse and 2nd. I've experienced a lag or jerkiness in reverse when the car is cold. I've also experienced a hesitation in 2nd after coasting, at low speed and then hitting the gas again. Makes me think that solenoid is less than optimal but it's always been that way. Otherwise, I have no issues. Went to the track tonight and probably made eight passes? Need to count my time slips.

[JamesRS5]

I feel the same lag with reverse but I just had it down as a characteristic of the box.

[Ape Factory]

You're most likely right. My gearbox may have always been like that, I didn't really pay attention to it until I flashed stage 1 but I was probably paying closer attention to everything after the flash. The reverse hesitation goes away if I let the car idle for another 30 seconds. Just found it odd I had similar symptoms in R and 2nd especially in relation to the shared components. I suppose I'm really hunting for a reason to pull my mechatronic apart, LOL. I'm sure I could gain a few tenths by freshening everything up.

[SteveRS4]

Did Autohaus run the Basic Settings procedure after their repairs? Assuming they use VCDS on their computer then ask them to run the following:

http://wiki.ross-tech.com/wiki/index...rbox_(DSG/0B5)

Ive have tried this and get this up [Erase counter for start and stop processes]
request out of range, temp was 52c and tried again at 56c any ideas guys ?

Sent from my SM-G920F using Tapatalk

[SteveRS4]

Sorry forgot to add the other two procedures complete successfully only reason i wanted to do this is I've been getting a hesitation as such maybe more like a loss of power when pulling away from stand still the gears change up quickly to about 3rd or 4th i have to lift throttle and reapply for it to catch a gear and go ! Its been dangerous when pulling out and need to be quick it only happens once after about 10/20min of driving from cold and then i can't get it to do it again ? There are no fault codes at all ? Thought id give this basic settings a try to see if it helps ??

Sent from my SM-G920F using Tapatalk

[JamesRS5]

Is this since the stage 2 flash Steve?

[SteveRS4]

Yes never done it before the stage 2 flash

Sent from my SM-G920F using Tapatalk

[SteveRS4]

When i flashed the ecu/ tcu i never turned off the ignition between flashes as I've read others have, do you think this would of made a difference ? It seems ok apart from this gearbox issue when pulling away ?

Sent from my SM-G920F using Tapatalk

[JamesRS5]

I would probably load the software again following the correct technique and see if it makes a difference, I've not read of anyone else having this problem.

[SteveRS4]

I would probably load the software again following the correct technique and see if it makes a difference, I've not read of anyone else having this problem.

Am i able to go back on JHM server and re flash it all again ? Would you do both ECU and TCU again or just TCU ? Also what is the correct technique to follow ? Sorry about so many questions i never got any info from JHM when i did this i was just told via an email to connect to there server and flash both ECU/TCU onto the car !!! Many thanks James

Sent from my SM-G920F using Tapatalk

[JamesRS5]

You'd have to speak to JHM on that Steve but it sounds suspiciously like the TCU flash isn't quite right, the OE software rushes through the gears in an attempt to improve economy, the JHM TCU tune holds gears longer so something didn't work out.

I don't have the tune....yet so I can't advise on how the correct procedure in loading.

[SteveRS4]

Thanks James, I've read up on the stage 2 a bit more from this site to see how you do it and after you flash the ECU you have to turn key off wait 65 sec then back on wait 45 sec run TCU turn key off wait 65 sec turn key on wait 45sec start car your done !! I think that's right I've done both flashes again today so will see how it goes ? If not ill get in contact with JHM. Thanks again

Sent from my SM-G920F using Tapatalk

[SteveRS4]

P.s James i thought you had the stage 2 already ? I know you have the trans cooler how you getting on with yours ? Mine is working ace took mine out today and give it some stick was a bit slippy tho as the U.K weather is wet n windy and cold but the car loves the cold air still managed to get the fans to cut in tho on the trans cooler so it's doing it's job i also hit the rev limiter as all four wheels lost traction haha that was fun ! Will be interesting to see how yours copes with the hot weather where you are in the summer, i bet you dont miss the U.K winters you lucky man !!

Sent from my SM-G920F using Tapatalk

[JamesRS5]

I've not installed the cooler either! I would like to say I was actually going to hold off until the temperatures start to climb in May so I can do some back to back testing of the difference it makes but the truth is I've been too busy to get anything done (including moving home 1 week before Christmas).
Stage 2 will probably go on just before this or immediately after the cooler if I can find a company here in Dubai to load the software, there's 45 floors between my car and my apartment so internet connectivity is an issue.

I've been here 9 years, I miss the UK summer, you really can't beat the summers at home but the other 360 days I don't miss

[SteveRS4]

I've not installed the cooler either! I would like to say I was actually going to hold off until the temperatures start to climb in May so I can do some back to back testing of the difference it makes but the truth is I've been too busy to get anything done (including moving home 1 week before Christmas).
Stage 2 will probably go on just before this or immediately after the cooler if I can find a company here in Dubai to load the software, there's 45 floors between my car and my apartment so internet connectivity is an issue.

I've been here 9 years, I miss the UK summer, you really can't beat the summers at home but the other 360 days I don't miss

9 years is a long time away you must love it there ? Yeah U.K summer are great just not enough of it like you say.

Would be good to do some back to back testing if you can with the cooler and post up the results ! I know how it is moving house its a pain in the ass I'm looking at moving very soon but I'm staying in the U.K 42 floors wow that's mental i hope you have a lift lol, you will have to find a way to get the stage 2 you will love it i had a stage 1 before from MRC it was a good tune but this is another world you will love it !

Sent from my SM-G920F using Tapatalk

[iggyhumph]

Hi Guys,

Would really appreciate some help regarding my gearbox malfunction fault with my 2011 Audi SQ5 3.0 TDI common rail - 7 Speed DSG gearbox. When reducing speed its holding on to 2nd gear when pulling up to junctions then gives a surge and selects 1st. This is when the dashboard lights up with the gearbox malfunction warning. It happens in both Sports or Drive mode. All other gear changes are fine. I've just had the wiring harness in the mechatronics unit changed and also 4 solenoids but I still have the same issue. Car is in the shop now and the mechanic is saying he needs to change the circuit board. He doesn't seem confident it will fix the problem. He was confident the mechatronics repair kit would have resolved the issue but it didn't

I previously got the gearbox software upgraded by Audi from version 11 to version 13 but it didn't cure the problem. The gear box error is P187B00 “Gear selector 2 engaging process not successful.

Some other background to note is that this is a replacement gearbox from another Q5 2012 with 49,000 KMs. Had the problem above since it was installed

Please let me know if there is any other information I should share to help identify the issue

Graham (now living close to Sydney Australia and left the UK in 2007 and don't miss the UK summers and certainly not BREXIT)

[iggyhumph]

Hi Guys,

Would really appreciate some help regarding my gearbox malfunction fault with my 2011 Audi SQ5 3.0 TDI common rail - 7 Speed DSG gearbox. When reducing speed its holding on to 2nd gear when pulling up to junctions then gives a surge and selects 1st. This is when the dashboard lights up with the gearbox malfunction warning. It happens in both Sports or Drive mode. All other gear changes are fine. I've just had the wiring harness in the mechatronics unit changed and also 4 solenoids but I still have the same issue. Car is in the shop now and the mechanic is saying he needs to change the circuit board. He doesn't seem confident it will fix the problem. He was confident the mechatronics repair kit would have resolved the issue but it didn't

I previously got the gearbox software upgraded by Audi from version 11 to version 13 but it didn't cure the problem. The gear box error is P187B00 “Gear selector 2 engaging process not successful.

Some other background to note is that this is a replacement gearbox from another Q5 2012 with 49,000 KMs. Had the problem above since it was installed

Please let me know if there is any other information I should share to help identify the issue

Graham (now living close to Sydney Australia and left the UK in 2007 and don't miss the UK summers and certainly not BREXIT)

[JamesRS5]

See post #15 above, was this done after the replacement gearbox was fitted?

[dubai_rs5]

The battle continues with this mechtronic issue....

Autohaus sent back the mech unit to the repair shop in Dubai for a second attempt but there were still clutch control issues when it was returned. They offered me a full refund for this repair and recommended a factory refurbed mech unit from Audi costing c $3.5k which comes with a 2 year warranty from Audi.

We went ahead with this but on installation of the refurbed mech unit, they had an error code for the gear sensor module (g676) which is inside the main gearbox housing. This was then replaced along with the moduleÂ’s wiring harness - a big job involving removal of the gearbox and engine. Unfortunately the new gear sensor module is producing the same error code, despite Autohaus advising theyÂ’ve followed the correct installation and adaptation procedures for the mechatronic unit.

Any ideas what the problem is? Could it be as simple as a software update?

TIA

[JamesRS5]

Some info on this from the Ross Tech website:

https://forums.ross-tech.com/showthr...ox-Malfunktion!

Make sure they ran the calibration in the correct order:

Coding

When replacing this Mechatronic unit Component Protection fault code(s) may be stored.
Basic Setting

Prerequisites:
Transmission fluid level correct
Transmission fluid temperature between 40°C - 100°C. (one user reports this needs to be below 60°C)
TCM fault free however it is strongly recommended to check/clear all Powertrain controllers faults also.
Key on, Engine off
Selector lever in P

All 3 Basic Setting operations need to be completed in the order listed below

[Select]
[02 - Auto Trans]
[Basic Settings - 04]

Select Erase counter for start and stop processes
[Go!] to activate the Basic Setting.
After the result of Finished Correctly or Not Running appears click [Stop]
[Done, Go Back]

Start the Engine and leave the Selector lever in Park

[Basic Settings - 04]
Select Clutch valve calibration [Go!] to activate the Basic Setting.
After the result of Finished Correctly appears click [Stop]

Select Distance sensor calibration
[Go!] to activate the Basic Setting.
Clunking noises from the transmission are normal
After the result of Finished Correctly appears click [Stop]
[Done, Go Back]

Switch off Ignition, wait 10 Seconds and switch it back on.
[Fault Codes - 02]
Check and clear any fault codes
[Close Controller, Go Back - 06]
Perform a test drive and check for fault codes again after doing so.

[dubai_rs5]

James - thanks, very helpful as always. Is this the calibration procedure recommended by Audi or an alternative one developed by Ross-Tech? I think Autohaus have been following the Audi procedure but the problem must be related to the new mech unit, as we didn’t have this sensor fault previously when the car’s original mech was repaired and refitted.

Interesting piece from the Ross-Tech forum:

“If the Mechatronic controller is replaced, it will be necessary for the vehicle to have the end-of-line programing / Parameterization, this is completed with an online connection to the manufacture, VCDS does not perform these online functions at this time.“

Do you know what’s involved with this procedure? Seems unusual that it couldn’t be done via conventional VCDS programming?

[JamesRS5]

Well they install a factory refurbed unit so if this contained a replacement Mechatronic Controller then it could well require the dealership plug in to set up the parameters.

You've replaced all the parts now including the position sensors, just make sure they have followed the procedure listed above before you go any further and start paying Audi Dealership prices.

[99PanozAIV]

I just got rid of my 2008 S4 Avant (115,000 miles) because of almost certain Mechatronic problems. I had spent over $2,000 last year on repairs (multiple leaking engine gaskets) and then the transmission started acting up. I found a good transmission shop that worked on ZFs and they ran a scan on the transmission and couldn’t see any codes. I drove it a bit more and it was still doing the 2-1 hard downshift and shifting irregularly in other gears. I went back to them and asked them their opinion. The owner and his lead tech both said, almost simultaneously, sell it while I can. They said, in their opinion, I was just at the start of a long list of things going wrong. We recently traded it and my wife’s car on something else. Disappointing.

The battle continues with this mechtronic issue....

Autohaus sent back the mech unit to the repair shop in Dubai for a second attempt but there were still clutch control issues when it was returned. They offered me a full refund for this repair and recommended a factory refurbed mech unit from Audi costing c $3.5k which comes with a 2 year warranty from Audi.

We went ahead with this but on installation of the refurbed mech unit, they had an error code for the gear sensor module (g676) which is inside the main gearbox housing. This was then replaced along with the moduleÂ’s wiring harness - a big job involving removal of the gearbox and engine. Unfortunately the new gear sensor module is producing the same error code, despite Autohaus advising theyÂ’ve followed the correct installation and adaptation procedures for the mechatronic unit.

Any ideas what the problem is? Could it be as simple as a software update?

TIA

[dubai_rs5]

Finally got the issue solved. In the end I took it to Audi as the independent shop were out of solutions. Audi just ran the adaption procedure for the drive position sensor - this apparently needs be done when the mech unit is replaced and is similar to the clutch/selector adaptation where the new circuit board “learns” the different positions for the gear lever. No firmware updates were needed. Car driving perfectly now. A shame the independent shop didn’t figure this out and it would have avoided replacing the drive position sensor and a trip to Audi which added about $1.5k to the total bill. All-in the work came to about $5k which is less than others have experienced, so I’m relieved to some extent. But it does make you question your faith in the car and whether you should just get rid of it for peace of mind.

On a side note Audi mentioned one of the gear selector forks (1/3 I think) was stiff when they removed the mech unit to check the selector forks. I haven’t noticed any symptoms when driving and further inspection and repair probably means open-heart surgery on the gearbox, so I’m not going to take any action for now. But I am wondering what might be causing this and if the problem is going to be progressive and eventually result in an expensive failure of the mechanical side of the box? Also surprising to hear this from Audi as the car only has 60k kms and the mechanical part of the transmission seems to be very robust by all reports?