p1811 or p01811 on 03 grand prix se 144,000mi 4t65e transmission

**2003GrandPrixSE** · 05-19-2013

Had delay in shifting from dead stop, changed fluid/filter-no help. Took to dealer, read code p1811(since this is non-emission code trans manual states will not give dummy lite), recommended replace trans $3000!--no thanks. Read on this forum bout solenoids(aka valves) (thanks to all who posted) and for about $300 in parts and a full days labor with buddy, shifting like new for past month. Here are a few details:
1. Download trans manual from ATSG for $30, great diagrams etc nothing in Haynes/Chilton gonna help(except torque settings for everything your gonna pull apart to get to this).
2. Replaced 4 solenoids in trans, was confused til realized some go by different names with same part #. Basically there is 1 TCC(TorqueConverterClutch) solenoid, 2 shift solenoids(identical, same part #), and 1 EPC (Electronic Pressure Control) aka Control solenoid. Ordered from rockauto, see below:
3. Ran half can SeaFoam for bout 30 mile highway trip to flush trans.
4. Also ordered trans side cover gasket(O'Reilly Autoparts), med duty cooler kit and new motor/trans mounts(may as well do em now)-rockauto
5. Dropped pan n filter. Pulled wheel/hub/axle/strut from driver side after getting car nice n high. Axle puller free rental from Advance. Worked side cover bolts from above n below. Will need to undo cradle bolts for enough play to raise n lower trans. Side cover combo torx and metric bolts.
6. Solenoids easy to match up (by appearance/wire colors) and change. Replaced all 4 since cheap n not worth taking chance after this kinda labor.
7. Installed cooler (did not come with correct fitting in kit, just re-used old section trans line after flaring end).
8. Buttoned everything back up and completely solved problem.

Quantity

Return

2003 PONTIAC GRAND PRIX 3.1L V6

Transmission-Automatic : Control Solenoid

ACDELCO Part # 24227747

VALVE,TCC Pulse Width Modulation Solenoid w/4-SPD AUTO TRANS(MN7)

VALVE,TCC Pulse Width Modulation Solenoid w/4-SPD AUTO TRANS(M15)

1

ACDELCO Part # 24219819

VALVE,1-2,3-4 SHFT SOL w/4-SPD AUTO TRANS(MN7)

VALVE,1-2,3-4 SHFT SOL w/4-SPD AUTO TRANS(M15)

2

ACDELCO Part # 24225825

VALVE,PRESS CONT SOL w/4-SPD AUTO TRANS(MN7)

VALVE,PRESS CONT SOL w/4-SPD AUTO TRANS(M15)

**Tony Mendez** · 05-19-2013

Nice write-up

**2003GrandPrixSE** · 05-20-2013

Thank you, did bunch of research. Didn't want to let this car go, everything works great still.

**BillBoost37** · 05-20-2013

FWIW a shift kit would have bandaided the issue for much less. The soleniod in question was the EPC, another thing to keep in mind is GM didn't give a clearancing spec, some rebuilders have the code/issue after doing a basic rebuild. By doing the shift kit, that speeds up the shift and helps the issue from happening.

**Mr D** · 05-20-2013

Thanks for the Post! I have an '03 GTP, 135k mi. Shortly after buying it and getting it on the road, it developed the hard shift-bang problem. Started w/ a ZZP shift kit, which helped but did not fix it. Few months later, I did an on-car differential replacement. Then a few months ago, I installed a TEP shift kit w/ a bottle of Lucas, which worked great initially, but the slip-bang is steadily coming back, esp. when its hot. I'm working up the nerve to try for the solenoids. OP, can you add more info/answer few ?s 1) what type of support is needed for the engine? 2) what type of support is needed for the trans? Greatly appreciate you sharing the knowledge/your experience. Thanks again!

**2003GrandPrixSE** · 05-20-2013

We got the car sitting nice n high on some old Jeep rims, used jack stands as additional safety. Then used a jack with a block of wood under the oil pan or trans, you'll have good access to undo the trans mount once you remove everything from the wheel well on drivers side. You're gonna have to undo front engine struts so that when you jack the engine will tip back, at some points it will seem like its almost pressing against the firewall. Then it takes some trial and error in positioning the jack and how high or low(undoing the cradle lets you drop it) you go to get all of the side bolts out. And finally maneuver the side cover off. Metric bolts easy to reach from above with air cleaner removed, lower part of cover held on by Torx bolts. Surprisingly, dealing with I think 17 bolts, none stripped out or were a major issue to get out. Nice to have 2 people so one can adjust ht while buddy can see bolt location. We had engine hoist avail. but didn't need it. Jacks did fine. Feel free to ask any other questions.

**Mr D** · 05-21-2013

Great. Start with the basics. 1) Did you even remove right wheel?

Originally Posted by 2003GrandPrixSE

We got the car sitting nice n high on some old Jeep rims, used jack stands as additional safety.

. 2) Where did you support the car? Under what part did you put the jeep wheels? 3) How high does it need to be? Just high enough to work a jack under the oil pan to raise and lower cradle? Or does it need to be extra high? 4) you dropped the trans pan to drain, removed; left wheel/hub/axle/strut, both dog bones, air filter, & cradle bolts--did you remove anything else? Thanks again!

**BillBoost37** · 05-21-2013

Here's the way I get to it.

http://www.grandprixforums.net/how-t...ess-54448.html

**Mr D** · 05-22-2013

Thanks Bill. Gonna thread-jack. When you say, undo 15mm nuts for engine mounts and tranny mounts to subframe, do you mean the lower mounts? Do you undo the dogbones? Also, once the tranny side cover is off, will the solenoids (all 4 of them) be accessible, or is more disassembly required (I just want to replace solenoids--nothing else)? Thanks!

**2003GrandPrixSE** · 05-23-2013

We put the wheels under the sides bout where the scissor jack notches would be, don't need extra high because you have to work from above too. Everything you listed is correct, only reason we took off right wheel was to replace lower engine mount, had good amount of movement in engine when shifting from park to reverse, mount also had one bolt sheared off. Otherwise would not have touched that side. Once side cover is off, all solenoids are easily accessible. Good luck, Kevin

**BillBoost37** · 05-24-2013

To allow the drivetrain to lower far enough, i believe you do. If It's not in the writeup, then..geez I haven't done one in a while and think you need at least the driverside one.

**jasonderricko** · 09-16-2013

Originally Posted by BillBoost37

FWIW a shift kit would have bandaided the issue for much less. The soleniod in question was the EPC, another thing to keep in mind is GM didn't give a clearancing spec, some rebuilders have the code/issue after doing a basic rebuild. By doing the shift kit, that speeds up the shift and helps the issue from happening.

I am having hard shifting that starts when downshifting while passing, It throws an 1811 code and then shifts hard all the time until it is shut off.I am thinking on doing the shift kit first and then the PCS if necessary, but do you think I should do them both at the same time.

**BillBoost37** · 09-16-2013

Well.. a shift kit/bottle of lucas usually fixes it up. Because the issue is too long to shift and shimming the accumulator with the shift kit stops the long shift. Doing the pcs is a lot more labor than a shift kit.

**02NavyBlue** · 09-17-2013

I did the shift kit and it solved my max adapt problem. Never came back.

But since I like doing things right, I'm going to replace the part thats causing the problem which like bill said, takes a lot more labor. The main reason is because the pressure in the trans was the original problem, causing shifts to be slow. Putting a shift kit in speeds 1-3 shifts up not by pressure, but by means of stiffer springs/shims in the accumulator. So the TQ converter lockup and 4th can still be slow. Also it's just not good to have too low of line pressure in a trans if you don't drive like a grandma.

Also to people reading this in general, the OP has an 03+ style 4t65e. 98-02 requires a different PCS: Part#: 10478146

I've also been trying to make sure the shift solenoids stay the same after 02, but can't quite get answers from multiple sites. I've found two part numbers though: 24219819, and 84955. Are they the same thing? I'm thinking the 84955 is just an aftermarket part number. TEP says otherwise though.

**BillBoost37** · 09-18-2013

I don't question Dave.

**jasonderricko** · 09-18-2013

Originally Posted by 02NavyBlue

I did the shift kit and it solved my max adapt problem. Never came back.

But since I like doing things right, I'm going to replace the part thats causing the problem which like bill said, takes a lot more labor. The main reason is because the pressure in the trans was the original problem, causing shifts to be slow. Putting a shift kit in speeds 1-3 shifts up not by pressure, but by means of stiffer springs/shims in the accumulator. So the TQ converter lockup and 4th can still be slow. Also it's just not good to have too low of line pressure in a trans if you don't drive like a grandma.

On mine the problem is from OD/fourth on the freeway down to third - so if it only speeds up shifts 1-3 would it solve my issue until I get around to doing the PCS? It shifts great in every other situation and has 94XXX on the car.

**02NavyBlue** · 09-18-2013

Originally Posted by jasonderricko

On mine the problem is from OD/fourth on the freeway down to third - so if it only speeds up shifts 1-3 would it solve my issue until I get around to doing the PCS? It shifts great in every other situation and has 94XXX on the car.

So once you downshift from 4th to 3rd, then it starts happening? And only in that situation? I'm not sure if a shift kit would help that or not.

I know its 1-3 but I don't know if going down to 3 counts as part of it. But the shift kit dramatically improves downshifts with or without a problem to begin with.

**jasonderricko** · 09-19-2013

The most noticeable shift is from 4th down to third. The others seem fine to me, but this is my first gp, so i don't have a good baseline to compare it too. I ordered the shift kit already, so I will put it in, change the fluid to dex VI use some lucas and see what happens.

I'm going to try some seafoam as well.