GTP shifting hard, SES P1810

[GTP_gUyl67]

My grand prix started shifting very harsh the other day, and then set an SES light. I scanned the car and got a P1810 code, which is a malfuctioning TFP(tranny fluid pressure) valve. I did some searching and found out that the PCM controls these valves and if the PCM is not sending the right signals to the valves it will do this and cause the tranny to shift hard and set an SES light. I need to know why my PCM would not be sending the right signals. Im leaning toward a throttle position sensor, but dont know where to look for that. If anyone else has ever had this problem i would greatly appreciate any help. Thanks!

[StevePT]

Your PCS itself is going bad. Very common problem. Do a search here on "harsh shift PCS"

AC Delco Part #10478146

Check out RockAuto.com

They have the part at a very reasonable cost.

There's also gmpartsdirect.com but I was just there and added a $3 o-ring to my cart and it said S&H would be $45. That must be an error, but I didn't look into it much further.

Try it for yourself and see what they show for shipping.

[GTP_gUyl67]

Im normally good at the abreviations but what is the PCS? Where is it at and how hard is it to change. Thanks for your help! Your the only person that could actually give me a pretty good guess at the problem, on all the other forums im on nobody can tell me anything.

[richtazz]

the PCS (pressure control solenoid) is in the valve body of the trans, and can get sticky due to lacquer deposits from the fluid as it ages. Before going to the trouble of replacing the PCS, buy a bottle of Trans-X or Seafoam trans additive and see if it fixes itself. These two products work wonders on sticking valves/shift solenoids and may save you a ton of money.

[StevePT]

http://www.automotiveforums.com/vbul...d.php?t=398499

Here's a thread showing the PCS disassembled. Do a search for posts by the member "Flatrater" and keyword "PCS" you'll find good information.

Does anyone know of a picture thread of PCS replacement? Or at least some diagrams showing the location and general procedure for replacement. My mom's 99 Buick Regal GS is showing signs of a hard upshift when warm, so I need to get that replaced before it causes too much damage.

[BNaylor]

Originally Posted by StevePT

http://www.automotiveforums.com/vbul...d.php?t=398499

Here's a thread showing the PCS disassembled. Do a search for posts by the member "Flatrater" and keyword "PCS" you'll find good information.

Does anyone know of a picture thread of PCS replacement? Or at least some diagrams showing the location and general procedure for replacement. My mom's 99 Buick Regal GS is showing signs of a hard upshift when warm, so I need to get that replaced before it causes too much damage.

Nice post StevePT. This is my recommendation, unless you happen to own a tranny shop or have a lot of patience its better to have a shop replace the PCS solenoid. I do not classify it as a DIY job. PCS replacement runs around $400 - $500 with the part.

In the case of poor Mr. Peter Solarik, he had the PCS replaced but was either too late or there were other parts in the 4T65E tranny that were worn out or damaged. A few months later he had to spend big bucks and get it rebuilt.

Personally, I'd go with Rich's suggestion. Either Sea Foam, Trans X or Lubegard additive for the time being. It worked in my wife's '99 Regal LS. Costs under $10.00.

The PCS solenoid is located on the valve body which happens to be located under the side cover assembly of the driver's side of the tranny.

At the top of the tranny you'll see a 25 way electrical connector that supplies the commands from the PCM, range switch, and 12v from the engine compartment fuse box. To get to it, you have to drain the tranny of ATF and remove the side cover and everything in the way which will probably include the driver's side axle half shaft.





Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[GTP_gUyl67]

Could this really be the only thing it could be? Becuase its not like it gradually started shifting hard. It was on day everything was normally and then the next day it was like this. I kinda find it hard to think that this valve would just stick in a position over night. I put this motor and transmission in myself about 5 months ago with not even 60,000 miles on them and ive only put maybe 2,000 miles on since then. The tranny fluid was also changed right after i did the engine and tranny swap. Also another thing 2 days before any of this started happening, i changed the left side half shaft and also put a different exhaust on it. Drove it for a little bit and it was fine, next day i drive it and its shifting very hard and then an SES kicked on. Im trying to make sure everything outside the tranny is ok before i determine that its something inside the transmission. I appreciate all your guys help!

[BNaylor]

Originally Posted by GTP_gUyl67

Could this really be the only thing it could be? Becuase its not like it gradually started shifting hard. It was on day everything was normally and then the next day it was like this. I kinda find it hard to think that this valve would just stick in a position over night. I put this motor and transmission in myself about 5 months ago with not even 60,000 miles on them and ive only put maybe 2,000 miles on since then. The tranny fluid was also changed right after i did the engine and tranny swap. Also another thing 2 days before any of this started happening, i changed the left side half shaft and also put a different exhaust on it. Drove it for a little bit and it was fine, next day i drive it and its shifting very hard and then an SES kicked on. Im trying to make sure everything outside the tranny is ok before i determine that its something inside the transmission. I appreciate all your guys help!

Didn't you do an engine and tranny conversion to a L67? Sounds like you are getting some kind of side effect from the upgrade. 2,000 miles since you did it is probably just enough time for any bugs to show up.





Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[streetlam]

Hey, everyone! First post here... and I hate to say, I have the same problem. Hash shifting, whining noise and P1810 =\
My car it's a 2001 Pontiac Grand Prix GTP with the 4T65E HD tranny and L67 3.8 II series Supercharged.

I want to know if there is any newer part for the PCS, since I recall someone saying that AC Delco Part #10478146 itself will probably fail again. I'm getting deseparate with this thing, since febrary (when I bought my car) it had it... and didn't pay much atention, nowadays I get this problem every time... BTW, if a friend of mine already works with manual transmissions, can he help me with this? How difficult is to change the PCS? And do I still stand a chance to save the tranny with Trans X, Lubegard or Sea Foam?

And what TAPS stands for? How do I calibrate that?

PS Sorry to bring a topic so old to life.

[BNaylor]

Originally Posted by streetlam

PS Sorry to bring a topic so old to life.

Welcome to AF.

Sorry but we prefer that that old threads are not resurrected for any further discussion. Start a new thread and I'm quite sure someone will help. In the meantime, thread closed.