Making Transmission throw P1811 code...

[yonkerse]

Hey guys,

I have been experienced the hard shift a couple times in my 2005 SLE with 85000 on it. I'm well aware of the PCS throwing the P1811 code, and have talked the dealer many times and agree its the PCS!

Some of you guys may ask why i want this to happen, reason being I only have 1000 miles left on my warranty and dealer said they would cover it, IF I can get the code to display on a code reader. I have had the code displayed before (on my scangauge), but didnt realize the OBD II resets itself after so many starts, so unfortunately i have lost the code.

Does anyone have any ideas or suggestions to get this code to display once again? Driving styles? Manual shifts? anything?

The couple times it has acted up on me, the transmission seems to be completely warmed up to operating temperature...

Thanks guys!

[00Beast]

It should be stored as a history code. It's like 40 key cycles that it resets, so unless you start your car like 10 times a day, I don't think you've reset it.

[yonkerse]

Well it happened the second time two days before my scangauge was installed, and they have been installed for about 3 weeks now..so im sure im past the 40 key cycles. Not sure of a way to pull up history codes...

[01bonneSC]

Long trips, get it heat soaked.

[golfyeti]

Long trips, get it heat soaked.

X2 - and then driving it hard is when mine used to act up.

[yonkerse]

I will try the longer trips and getting on it to see if i can trigger the code...

golfyeti - did you have your PCS replaced or a tranny swap? Wondering what you did when you sayd "mine used to act up."

Thanks for suggestions guys!

[golfyeti]

The problem went away after I installed a 180 degree thermostat and I must add that I also got at the same time the Intense PCM with it's better fan settings. The 180 Tstat predominently was keeping everything cooler. Less heat and less likely to trigger PCS "confusion" as to proper pressure under excess heat. That's my take on the issue from what I have read. Some will suggest a new PCS or a shift kit but try a $10 stat first.

I used to turn off the road. Turn off the car for 10 seconds and it would go away, unless things then got even hotter. Anyway the occurence was getting to be a couple times per week, but after the stat change some 4 years ago it happened again only once - city driving on super hot day like at 98 F.

[yonkerse]

Hey golyeti,

Thanks for the info. I actually already have the 180 degree thermostat ordered and will be putting that in pretty soon. If I continue to have a harsh shift, i will probably end up installing a trans cooler as well. Im going to really try to get the dealer to get this replaced, just went under 1000 miles on my warranty today... :(

I never thought about turning the car off to reset everything when it acted up, will give that a try once i get the code and it acts up!

[yonkerse]

Little update:

Drove the car home last night after the tranny was pretty well warmed up, seemed to hold a pretty steady 140-150 on the way home. Jumped on it pretty hard every turn i made and even stopped on some back country roads and jumped on it, got the tranny up to about 160 degrees and didnt have any shifting problems at all. Once my tranny got to around 160 (with stopping and jumping on it) my scangauge stopped displaying trans temp and it hasnt displayed all day today...any suggestions? All other parameters work just fine, just doesnts how anything for trans temp...? I continued rest of the way home, with normal driving and doing a few more pulls and the thing shifted flawlessly the whole time...figures..haha

I also noticed that my car has a slower shift time when accelerating hard (around 2200 ms) compared to around 555-700 ms when accelerating casually...is this common? I have also heard that a slow shift will throw the P1811 code....must be a slower shift than 2200 ms because its still not showing any codes :(

Thanks for continuing to help!!! Its greatly appreciated!

[ironoxide]

I just had my PCS replaced 3 days ago (02 Bonneville - 102K). The car never displayed the 1811 code that I could read with my OBD II scanner; never flashed the code on the dash. The dealer was able read the code with their scan tool. They also test drove it and stated on the invoice that the PCS reads too low amps, which caused the pressure to increase and made the shift point hard and erratic: PCS bad internally.

I'm guessing that your PCS is possibly just starting to act up. Initially, my car would go into adaptive shift mode about once/wk, and this would go away if I turned the car off and restarted it after a few minutes. Always happened just driving around town after it was warmed up. Then, it got to where I really had to do something about it and had it replaced. There's a lot of labor involved, so the expense of having it replaced is high. After finally having it replaced, it shifts like new and renewed my confidence in the car.

People suggest all kinds of alternative solutions to this - but I'm of the opinion they should just have the PCS replaced.

[00Beast]

ironoxide, I do agree that replacing the PCS is ultimately the best option, however most members on this site would rather do a few things to cover up the symptoms that cost $100 and make it last a few years than spend $600 to get the same results.

[RJolly87]

Also bear in mind that warranty is a factor. He was trying to get it to throw the code while still under warranty so that it may be properly repaired.

[ironoxide]

Hey Beast:

That's right dude. Replacing the PCS is ultimately the best solution. If you want to continue to suggest band aid alternatives to most members of the site you claim to speak for, go for it. Not saying they won't work - or for how long - and no big deal - when they don't work - the problem will just persist. In any event, based on what I learned, by the transaxle going into adaptive shift mode, there is no immediate concern for it being damaged. No harm done.

[yonkerse]

I thought i saw a member on here recently who actually had replaced the PCS himself IIRC? Does anyone know who that was? I have been trying to get the car to throw the code but havent gotten anything out of it.

No doubt in my mind the PCS will be replaced in my car in spring, either if i do it or if i have someone put it in...Really appreciate the feedback guys!

I have appreciated Beasts ideas, has certainly helped in other aspects of the car! No need to get heated here!

[ironoxide]

What I ran up against is (1) most people don't have the tools to troubleshoot and identify a bad PCS themselves, (2) if you did have it diagnosed by someone else and knew for certain that it was bad, it's not only time consuming to replace it (ALLDATA states 5 hours), it's not an easy job. With the right amount of background knowledge and tools, you could somehow make it happen?

To make my point: I gave my car to a reputable mechanic with ran his own garage and had other mechanics working for him. A decent place. He who drove it for a week. Yeah, a week. He knew something was causing it to go into the adaptive shift mode, but didn't know what. He would not say with certainty that it was the PCS. The dealer figured it out in 10 minutes.

The dealer quoted me $1336.00 for the repairs and a fluid changed. I just about fell over. I talked to the service manager and asked if they would do the job for $1000.00. Still high, but I wanted the dealer to do it with GM parts - and I wanted it done right - and he agreed. It took them more than the 5 hours ALLDATA suggested it should take.

What are the alternatives? Change out my thermostat? How would that make the car shift any better? That makes no sense. Then, it was suggested that I could install a shift kit to band aid it. Pull my pan, drain fluid all over, install a shift kit, and HOPE the car works better? Not for me. I need a reliable car to get back and forth to work with that doesn't shift all funky because of a bad PCS and a band aid shift kit. Same with a trans cooler.

If someone were to do this repair, document the steps and take photos of the procedure - that would be cool.

[01bonneSC]

My car does not do it now that it is cold out. So its def heat related, it gets overheated, then messes up. That shift kit just overtakes what the PCS does, bypasses the function of the PCS.

EDIT::: Do a search for how to reaplace it. I know theres been a couple people who did. Drop driver side of subframe, wiggle out pan, theres a clip holding the PCS in and undo the connector, then reverse to put back together, IIRC.

[LeSabre in Buffalo]

Agreed with 01bonneSC, it's better now that it's cold out.

The TransGo shift kit in my Buick does a darn good job masking my failed PCS. Whatever, it's another job I'll leave for the transmission folks when the transmission needs rebuilding. The shift kit went in during a pan drop pretty easily. Pulling the transmission is something I'll gladly leave for professionals.

[yonkerse]

Hey Guys,

Yet another update:

Today we had our worst winter day of the year, around 18 degrees, gusting winds around 40 MPH, and heavy lake effect snow accumulating around 8 inches and counting. I was at my parents house when this started and was driving back to to school about 45 miles away.

I get heading out, and while running around 45-50, i notice my car not shifting into overdrive, when usually it shifts in around 40 MPH. I come into a small town and catch a light, go to take off and my car gives me a hard shift (shift time of 50 ms). I had a couple stops until I got back to country roads, and EACH time, the car would have a hard shift during the 1-2 shift, and also the 3-4 shift, the 2-3 shift was FINE...

Checked DTC's and i see this:



I was shocked but happy to see this as my car is 600 miles out of warranty. I was surprised, because my car has only acted up like this before when transmission was completely warmed up, not 20 minutes into my trip and the coldest day of the year....

As I mentioned before, when I was driving my car home a couple weeks ago, driving it hard and trying to get the car to act up. During this process, my scan-gauge stopped displaying the transmission temp.

After checking my DTC's and displaying code today while acting up....this is now what my transmission temp reads.....



I know this is some type of glitch, but any ideas of how to get it to read accurately again? Could I unplug it from the OBD-II, wait a couple seconds, and plug it back in?

I'm really going to limit my driving and take the car to the dealership on Wednesday after my finals this week and have it checked out and HOPEFULLY get the PCS replaced!

Thanks for keeping in contact with the thread!

[yonkerse]

That first pic is indeed the P1811..turned out blurry since I was driving while taking the pic! haha

[ironoxide]

Mine would go into adaptive shift mode when I was driving it like granny would - waiting in line at stop signs, drive throughs, etc. I seemed to be able to avoid having it act up by accelerating a little harder with it, and avoiding stop and go...