: Spontaneous Down Shift to 1st while driving 50 MPH in Sport Mode - Anyone else have?



helffric
04-16-13, 12:43 PM
I picked up my 2013 new CTSv automatic on April 1st. Has anyone else had this kind of problem?

I put the car in manual shift mode by moving the shift knob right to manual mode (but letting the car do the shifting). All of a sudden the transmission started downshifting all the way down to first gear even though I was going 50 MPF, was not pushing down on the accelerator pedal, and was already at high RPMs (as it was shifting down).

I took it out of M by moving back to automatic via the shift knob. When I moved it right back to manual, it did it again. Then even though I moved the knob back and forth from automatic to manual it no longer would put it in manual mode (as indicated by the lights on the display in dashboard).

I was not using the paddles on the steering wheel before or during this event.

However, the next day, I couldn't get it to repeat this bizarre behaviour reliably (it happened one other time).

I haven't gone to the dealer yet on this but because I cannot reliably repeat it, I suspect between manual, sport, and DSC there is some sensor thing going wrong or? but what?

Has anyone else experienced this? Any tips on what's going on and how to get it fixed?

Thanks, Audrey

RaVeNous
04-16-13, 01:43 PM
I believe I saw a post about this on here or the "other" forum by someone else having the same issue. The dealer had to replace the whole shifter box but it solved the problem.

1997BlackETC
04-16-13, 02:13 PM
Hard to believe it went into first @ 50 mph, that would have the engine turning like 20000 rpms or so. Should definatley be checked out by the dealer though, this is not normal, the car should act docile when in either sport mode or manual mode unless you beating the snot out of the car.

marcusp23
04-16-13, 02:57 PM
Is your left paddle shifter stuck?

Worth a shot

Chrispy
04-16-13, 04:00 PM
Did you have an accidental right foot spasm? Happens to me all the time...

shchow
04-16-13, 05:14 PM
Don't think you were doing 50 in 1st...
It may have just felt like it...

ClarkkentCTSV
04-16-13, 05:22 PM
You could have accidentally downshifted when moving the shifter knob into sport mode. The shifter knob on my car is very sensitive to the touch and shifts very easily in manual mode. It happened to me once while racing. I had my hand resting on the shift knob and accidentally downshifted due to a slight movement with my arm.

helffric
04-16-13, 11:12 PM
Don't think you were doing 50 in 1st...
It may have just felt like it...

Agreed. As soon as it started its downshifting I moved the shift knob back to automatic. It was shifting as fast as possible. Quite shocking. It was starting from 5th (I think) and I think it had reached 2nd by the time I got to it.

Stillborn
04-16-13, 11:19 PM
if you never engaged sport mode to manual mode (either by hitting shifter or buttons) you would never know what gear it was in as it doesn't display numbers on the dash until you send it into manual mode as stated.

helffric
04-16-13, 11:20 PM
Is your left paddle shifter stuck?

Worth a shot

If so, it didn't stay stuck. I'll keep it in mind to check next time it happens. Although, I must say when it's in the middle of this I'm rushing to get it out of this mode to avoid damage.

Stillborn
04-16-13, 11:24 PM
i think your just not use to it hanging in the upper rpms as its suppose to do in sport mode. just drive the car a few weeks and get use to it. it has a rev limiter for safety reasons. if you're not bouncing off the limiter then everything is fine.

helffric
04-16-13, 11:37 PM
You could have accidentally downshifted when moving the shifter knob into sport mode. The shifter knob on my car is very sensitive to the touch and shifts very easily in manual mode. It happened to me once while racing. I had my hand resting on the shift knob and accidentally downshifted due to a slight movement with my arm.

Interesting. I'll try to recreate the multiple shift with a longer hold of the shifter knob in shift position. It was the fact that the car was shifting immediately down (seemingly) through all the gears that made me think that the car was initiating it all without direction from me.

DiamondWhtV
04-17-13, 06:15 PM
I'm also going with the sticking paddle shift switch. But it also sounds like the shift control is going haywire. Better see the dealer and investigate. You don't want to get stuck with a transmission shifting problem somewhere and need to tow the vehicle. I always get bad vibes thinking about towing the V.

helffric
04-17-13, 08:00 PM
Well, it took awhile but I recreated the problem again, but still not sure what I'm doing differently to cause it to start than times when it shifts as expected. Once in the mode it continues to do it until at least previously, the next time I drive it. However, I did also stop the car, turn off the engine and start it again with it continuing the symptoms as soon as I put it in M mode.

A couple more tidbits.

In this mode, the car switched back and forth between manual and drive as indicated by the display multiple times (while stopped at a light and in 1st gear, switching back and forth approximately every 2 seconds, ie it took about a seond per switch) although I was not touching either the paddles or the stickshift (which is to the right, ie M).

Also when in this mode neither pushing the paddles nor the shift knob caused any shifting.

I was unable to recreate it by holding the shift knob or shift paddle on for a long period of time.

It's definitely aiming for 1st gear jumping through all the gears as quickly as possible.

If I'm lucky, I'll be able to get it in this mode on the drive to the dealer (rueful smile).

helffric
04-30-13, 04:41 PM
The dealer agrees there is a problem. Was able to drive it there while it was happening to show them. Not reproducable on demand. There is nothing in their databases from GM on it. They think it's a software problem. I'll update the thread as further information develops.

helffric
04-30-13, 08:08 PM
Mine does show the gear number even when not in manual mode, ie in sport mode with automatic shifting. Maybe we are just using different terminology. I'm determining whether it's in Manual based on the display, not whether the shift mode is on 'm' (but stills shows as in Drive -and in sport mode on the displays).

austin
04-30-13, 09:35 PM
The dealer agrees there is a problem. Was able to drive it there while it was happening to show them. Not reproducable on demand. There is nothing in their databases from GM on it. They think it's a software problem. I'll update the thread as further information develops.

Perhaps it's a bad downshift touch paddle switch on the backside of the steering wheel.. That's my best guess.

helffric
07-06-13, 07:21 PM
Dealer found problem. Here is their description:

'2505 diagnosed tap shift concern, no codes, no bulletins, no diagnostics in SI for tap shift inop, test drove found car would shift in and out of manual to auto and down shift to first gear on it's own. Took a snap shot of trans data, found driver request showed down shift and invalid, tested circuits at steering wheel tap shift switches circuit #`375 and 1996. Found circuits good, removed center console to gain access to shifter and connector X202, tested circuits #5526 and 1375, found eratic ohms readings. Called TAC case #71-1175477338; determined the micro switch internal to shifter is no good, replaced shifter and rechecked, found working as designed.'

Internal Module Failure:
8460670 Transmission Control Replacement
136 WM4

FC: Part#: 25824054

----------

Here is what we went through to get it diagnosed. Intermittent short (I believe on reflection it would only recreate on wet days).

April 30, 2013

John Enkler, Service Manager
Hudson Cadillac Buick GMC
2023 South Road
Poughkeepsie, NY 12601

Re: Description of Transmission Problem Experienced
on our new 2013 CTS-v, delivery taken April 1, 2013 VIN# 2GKFLTEKXC6341032

Dear Mr. Enkler,
As provided on April 18th, 2013, when we recreated the problem at the dealership, here are the symptoms we have observed of the intermittent transmission problem on our new CTS-v.
When in manual sport transmission mode:
Suddenly, the transmission spontaneously starts downshifting all the way down to 1st gear even though the RPMs were already high enough and the driver was not pushing down on the accelerator pedal. The driver shifted back to automatic mode as quickly as possible so as not to hurt the engine.
Once in this mode, the driver went to a parking lot to experiment under more controlled conditions. After a few iterations of the problem described above, a couple different symptoms emerged after switching in and out of automatic again once the problem was extant:
In one case, the display no longer indicated M (manual) mode, even though the driver was shifting with the shift lever. All requests by the driver to shift are ignored.
In another case, shifting up and down appeared reversed, ie a driver request to manually shift down didnt do anything, a driver request to manually shift up caused the transmission to actually shift down. Note: is it possible that this is what the car is doing when it spontaneously heads to first, ie does it think its shifting up in order to avoid too high RPMs, when its actually shifting down?
In another case, while stopped, the car continuously switched back and forth between manual and drive as indicated by the display (switching back and forth approximately every 2 seconds, ie about a second per switch). While this was occurring, the driver was not touching either the paddles or the stick shift.
The problem does not reliably re-create but it has re-occurred a number of times since we first got the car. Perhaps it is temperature related (it does seem more likely to occur after its been driven for some time)? Also, is it possible the car thinks its stopped when this occurs since it automatically goes to 1st gear in M (Manual) mode by plan once stopped?
We appreciate your attention in getting a fix for this problem as soon as possible as we are not comfortable driving the car in anything other than automatic mode until this is fixed. We are also concerned about possible engine and drivetrain damage due to unusual stress outside of normal design parameters.

June 19, 2013

John Enkler, Service Manager
Hudson Cadillac Buick GMC
2023 South Road
Poughkeepsie, NY 12601

Re: Continuing Description of Transmission Problem Experienced
on our new 2013 CTS-v, delivery taken April 1, 2013 VIN# 2GKFLTEKXC6341032

Dear Mr. Enkler,
Here are some additional notes and observations on our continuing intermittent transmission problem on our CTS-v since April 30th, when you were unable to diagnose the problem.
During early May, we tried to reproduce the problem a number of times, but were only able to do so when your repair facility was not available, including while on a trip home from PA on May 23rd. In these instances, the problem did not reproduce after the first instance.
On June 1st, a Saturday afternoon, the problem reproduced a number of times on the same trip, but stopped doing so after sitting (overnight).
On June 8th, a Saturday morning, the problem reproduced a number of times even after turning off the ignition for over 20 minutes, twice. At this point, we talked to Dave in service, who told us there was no transmission tech in and to bring the car in on Monday.
In the last case, the circumstances were as follows.
Was cruising without acceleration in 3rd or 4th gear and went into sport mode. Then, it either continued to shift down through the gears towards first or the manual gear number light blinked on and off continually. Sometimes, at this point, the gear number display would stay off at which time the car would no longer go in sports mode despite moving the shifter to M or trying to shift with the paddles.
We do not consider it reasonable that we are being told that although this problem is most likely a software problem which cannot be debugged at the dealership, and yet the dealership cannot ask the GM software engineers to investigate the problem given the symptoms because GM doesnt do this. And when we ask what will be determined if we recreate it again at the dealership, we get vague answers that do not suggest that software can be debugged this way; only detected hardware problems. But we already know no codes are created (as determined last time). And when we ask if the dealership could start replacing parts in order to eliminate possibilities, we are told GM doesnt do this either since no parts are called out via codes. With all these seemingly inconsistent constraints, its difficult to see how we are going to get a resolution.
As stated previously, we would like to know the plans beyond recreating the failure again at the dealership to resolve this problem as we consider it both a safety issue and a risk of damage to the cars engine and/or drivetrain.

The problem recreated on 6/10/13 again for the dealer.

Audrey

vincemcoupe
07-06-13, 08:08 PM
My '13 had the same right off the lot but seems to have resolved itself after a week's driving (with avoiding to use Sport or Ma

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My '13 had the exact same problem right off the lot. The problem seems to have resolved itself after a week's driving (with avoiding both Sport and Manual Modes). There was no action required from the dealer's part (although they had offered to put in a new centre console shifter) and so far the symptoms have not recurred and both Sport and Manual Modes are working flawlessly. Hopefully, your problem is just a simple and straightforward fix (as stated above) away. I won't be concerned about engine damage as the ECU knows better to ignore faulty shifts in an eventual and most timely manner. The rev limiter also takes care of the rest. It was a pain to not able to use Sport Mode for the little while though,

Cadillac Cust Svc
07-06-13, 08:52 PM
Dealer found problem. Here is their description:

'2505 diagnosed tap shift concern, no codes, no bulletins, no diagnostics in SI for tap shift inop, test drove found car would shift in and out of manual to auto and down shift to first gear on it's own. Took a snap shot of trans data, found driver request showed down shift and invalid, tested circuits at steering wheel tap shift switches circuit #`375 and 1996. Found circuits good, removed center console to gain access to shifter and connector X202, tested circuits #5526 and 1375, found eratic ohms readings. Called TAC case #71-1175477338; determined the micro switch internal to shifter is no good, replaced shifter and rechecked, found working as designed.'

Internal Module Failure:
8460670 Transmission Control Replacement
136 WM4

FC: Part#: 25824054

----------

Here is what we went through to get it diagnosed. Intermittent short (I believe on reflection it would only recreate on wet days).

April 30, 2013

John Enkler, Service Manager
Hudson Cadillac Buick GMC
2023 South Road
Poughkeepsie, NY 12601

Re: Description of Transmission Problem Experienced
on our new 2013 CTS-v, delivery taken April 1, 2013 VIN# 2GKFLTEKXC6341032

Dear Mr. Enkler,
As provided on April 18th, 2013, when we recreated the problem at the dealership, here are the symptoms we have observed of the intermittent transmission problem on our new CTS-v.
When in manual sport transmission mode:
• Suddenly, the transmission spontaneously starts downshifting all the way down to 1st gear even though the RPMs were already high enough and the driver was not pushing down on the accelerator pedal. The driver shifted back to automatic mode as quickly as possible so as not to hurt the engine.
Once in this mode, the driver went to a parking lot to experiment under more controlled conditions. After a few iterations of the problem described above, a couple different symptoms emerged after switching in and out of automatic again once the problem was extant:
• In one case, the display no longer indicated ‘M’ (manual) mode, even though the driver was shifting with the shift lever. All requests by the driver to shift are ignored.
• In another case, shifting up and down appeared reversed, ie a driver request to manually shift down didn’t do anything, a driver request to manually shift up caused the transmission to actually shift down. Note: is it possible that this is what the car is doing when it spontaneously heads to first, ie does it think it’s shifting up in order to avoid too high RPMs, when it’s actually shifting down?
• In another case, while stopped, the car continuously switched back and forth between manual and drive as indicated by the display (switching back and forth approximately every 2 seconds, ie about a second per switch). While this was occurring, the driver was not touching either the paddles or the stick shift.
The problem does not reliably re-create but it has re-occurred a number of times since we first got the car. Perhaps it is temperature related (it does seem more likely to occur after it’s been driven for some time)? Also, is it possible the car thinks it’s stopped when this occurs since it automatically goes to 1st gear in ‘M’ (Manual) mode by plan once stopped?
We appreciate your attention in getting a fix for this problem as soon as possible as we are not comfortable driving the car in anything other than automatic mode until this is fixed. We are also concerned about possible engine and drivetrain damage due to unusual stress outside of normal design parameters.

June 19, 2013

John Enkler, Service Manager
Hudson Cadillac Buick GMC
2023 South Road
Poughkeepsie, NY 12601

Re: Continuing Description of Transmission Problem Experienced
on our new 2013 CTS-v, delivery taken April 1, 2013 VIN# 2GKFLTEKXC6341032

Dear Mr. Enkler,
Here are some additional notes and observations on our continuing intermittent transmission problem on our CTS-v since April 30th, when you were unable to diagnose the problem.
• During early May, we tried to reproduce the problem a number of times, but were only able to do so when your repair facility was not available, including while on a trip home from PA on May 23rd. In these instances, the problem did not reproduce after the first instance.
• On June 1st, a Saturday afternoon, the problem reproduced a number of times on the same trip, but stopped doing so after sitting (overnight).
• On June 8th, a Saturday morning, the problem reproduced a number of times even after turning off the ignition for over 20 minutes, twice. At this point, we talked to Dave in service, who told us there was no transmission tech in and to bring the car in on Monday.
In the last case, the circumstances were as follows.
• Was cruising without acceleration in 3rd or 4th gear and went into sport mode. Then, it either continued to shift down through the gears towards first or the manual gear number light blinked on and off continually. Sometimes, at this point, the gear number display would stay off at which time the car would no longer go in sports mode despite moving the shifter to ‘M’ or trying to shift with the paddles.
We do not consider it reasonable that we are being told that although this problem is most likely a software problem which cannot be debugged at the dealership, and yet the dealership cannot ask the GM software engineers to investigate the problem given the symptoms because ‘GM doesn’t do this’. And when we ask what will be determined if we recreate it again at the dealership, we get vague answers that do not suggest that software can be debugged this way; only detected hardware problems. But we already know no codes are created (as determined last time). And when we ask if the dealership could start replacing parts in order to eliminate possibilities, we are told ‘GM doesn’t do this’ either since no parts are called out via codes. With all these seemingly inconsistent constraints, it’s difficult to see how we are going to get a resolution.
As stated previously, we would like to know the plans beyond recreating the failure again at the dealership to resolve this problem as we consider it both a safety issue and a risk of damage to the car’s engine and/or drivetrain.

The problem recreated on 6/10/13 again for the dealer.

Audrey
Hello Audrey,

I am glad to hear that the dealership was able to find the cause to the concern you were experiencing. I apologize that they were not able to diagnose the concern until now. Has the repair been completed on your vehicle? Please keep us updated on the situation! Thank you very much for your time.

Gregory W.
Cadillac Customer Care

helffric
07-06-13, 10:43 PM
Vince,

I expect you may have the same problem; certainly it was true with us that we could go weeks without being able to recreate it. Our dealer also suggested it would just go away. However, because it was intermittent and had to be in sport mode and I believe also that wet weather was also required, it took a long time to recreate at a time when the dealership had an opportunity to debug it.

Although I agree that the automobile had safeguards to protect the engine and transmission, since there was obviously something wrong with the controls, I didn't feel comfortable relying on this (as the protections may have been controlled in part by input from the messed up thing).

Anyway, keep an eye on it - you may find it coming back. Thanks for your update.

----------

Gregory,

Thanks for you post. The dealership made the repairs as stated. I believe this has fixed the problem given their description of what they found and did. I do want to live with it for awhile to confirm the fix since it has been an intermittent problem that was frustratingly hard to recreate and get fixed.

I have to say, we are still not happy with the whole thing because we never got a satisfactory answer on how code problems experienced by an owner get debugged. I am glad they were able to find something wrong mechanically; stating that it is a GM policy never to replace a part without a code called out nor to have a conference call between the owners, the dealership, and GM to discuss possible code problem scenarios was maddening.

It was placed all on us to recreate the problem (the dealership had already seen it once; they knew it was not operator error) with the dealership also suggesting it was probably just fixed spontaneously - without any details explaining how this could be (clearly wishful thinking on their part).


The dealership was strictly reactive, not proactive and were very satisfied with themselves that this was all they could do due to GM policy.

I'd love to know if this is an endemic problem, what is being done to determine this, whether a change should or could be made to have this kind of scenario detected in future with a code called out, etc. but I expect it would be useless to ask the dealership given past experience.

If you could let me know any of this or who to contact to discuss this, I would be obliged.

Cadillac Cust Svc
07-06-13, 11:20 PM
Gregory,

Thanks for you post. The dealership made the repairs as stated. I believe this has fixed the problem given their description of what they found and did. I do want to live with it for awhile to confirm the fix since it has been an intermittent problem that was frustratingly hard to recreate and get fixed.

I have to say, we are still not happy with the whole thing because we never got a satisfactory answer on how code problems experienced by an owner get debugged. I am glad they were able to find something wrong mechanically; stating that it is a GM policy never to replace a part without a code called out nor to have a conference call between the owners, the dealership, and GM to discuss possible code problem scenarios was maddening.

It was placed all on us to recreate the problem (the dealership had already seen it once; they knew it was not operator error) with the dealership also suggesting it was probably just fixed spontaneously - without any details explaining how this could be (clearly wishful thinking on their part).


The dealership was strictly reactive, not proactive and were very satisfied with themselves that this was all they could do due to GM policy.

I'd love to know if this is an endemic problem, what is being done to determine this, whether a change should or could be made to have this kind of scenario detected in future with a code called out, etc. but I expect it would be useless to ask the dealership given past experience.

If you could let me know any of this or who to contact to discuss this, I would be obliged.

Hello Audrey,

I apologize for the experience you have had with the dealership not being able diagnose your concern. At any part during this experience did you contact our customer care phone number and receive a case number? Or was this strictly just working with the dealership? If you could provide me with your name, contact info, VIN, mileage, and dealership that you have been working with in a private message, I would like to do some additional research on your behalf. I will be out of the office until Tuesday afternoon. Will it be ok to follow up with you on Tuesday after you send the information I requested? Thank you very much for responding back to me and I will be looking for your private message.

Gregory W.
Cadillac Customer Care

helffric
07-07-13, 12:57 AM
Thanks Gregory.

I will send you the requested information via private message.

Audrey

GMX322V S/C
07-07-13, 04:19 PM
Dealer found problem. Here is their description:

'2505 diagnosed tap shift concern, no codes, no bulletins, no diagnostics in SI for tap shift inop, test drove found car would shift in and out of manual to auto and down shift to first gear on it's own. Took a snap shot of trans data, found driver request showed down shift and invalid, tested circuits at steering wheel tap shift switches circuit #`375 and 1996. Found circuits good, removed center console to gain access to shifter and connector X202, tested circuits #5526 and 1375, found eratic ohms readings. Called TAC case #71-1175477338; determined the micro switch internal to shifter is no good, replaced shifter and rechecked, found working as designed.'

Internal Module Failure:
8460670 Transmission Control Replacement
136 WM4

FC: Part#: 25824054

----------

Here is what we went through to get it diagnosed. Intermittent short (I believe on reflection it would only recreate on wet days).
Thanks a lot for sharing. Having the car override command authority is unnerving to say the least!

----------


Hello Audrey,

I am glad to hear that the dealership was able to find the cause to the concern you were experiencing. I apologize that they were not able to diagnose the concern until now. Has the repair been completed on your vehicle? Please keep us updated on the situation! Thank you very much for your time.

Gregory W.
Cadillac Customer Care
Can you find out if there was a running part number change for this item for the '13 model year?

Cadillac Cust Svc
07-11-13, 08:04 PM
Can you find out if there was a running part number change for this item for the '13 model year?

Hello GMX322V S/C,

I did some additional research on your question and couldn’t find any documentation of a part change. I reached out to an internal resource regarding the question as well and was told to direct you to the dealership, that they may have the answer. If you would like, I could contact them regarding your question. Please private message me and let me know. Thank you very much for your time.

Gregory W.
Cadillac Customer Care

BaggerOne
10-09-13, 05:06 PM
Hello! I am having this EXACT SAME ISSUE. The first time, I brought it into the dealership and they replaced the shifter -- while they couldn't recreate the issue, they did see an error code and I think they ended up taking it to the Service Manager or involved Cadillac but they covered the shifter replacement.

Thought we were out of the woods.

Within a day, maybe have even been the SAME DAY as I took it home, it happened again!

I usually drive in sport mode, and i usually drive with the vehicle in either traction control off, or competition -- usually though just traction off.

It did exactly what everyone stated -- i was doing about 35-40 and it just started shifting fast down to first, but it never made it obviously since the vehicle was going fast - it got down to 2nd gear and the "2" started flashing like crazy. It obviously wanted to be in first gear......

I took it out of sport mode immediately. At the light, i tried to put it back into sport mode, nothing. No indication at all. I tried to shift manually, and nothing. no indication at all. The only way to reset it was to shut the vehicle off and turn it back on.

I cannot get it to reproduce, but it happened AFTER the dealer replaced the entire shifter. So i'm obviously concerned.

It's at the dealership right now and of course no codes, no reproduce, no nothing.

It DID happen however after the shifter was replaced.

Does anyone have any more details on this? What could it be? What should I have them look at? Is there a software update? Something else to look at?

It's a brand new 2013 CTS Coupe with ~800 miles on it. Letting it just "be" is not really want I want to hear after spending good $$$ on a new caddy.....

Any thoughts/ideas would be greatly appreciated.

Thanks!

gregs v
10-12-13, 03:51 PM
I had the same issue on my 2013 v. I took the car to the dealership and they reported that there was indeed an error code but not sufficient data to diagnose the issue. I continued to drive the car for another 6 weeks before another random down shift. In short the service manager here in Memphis did a great job as he knew I did not want the car pulled apart unless they had proof the control module was defective. Instead he was able to trace the fault back to a faulty shifter button on the steering wheel that would intermittently cause a high voltage signal to trip the gearbox into a fail safe mode. Since the steering wheel was replaced under warranty 3 months ago I have had no further issues.

You may be suffering from a different fault, but before you have the car pulled apart, ask for a new steering wheel!

Good luck.