Simple question on TCS

Some times when i get on the pedal at a good amount but not floor it, my front end shakes for half a second then resumes to accelerate. MY question is, is this my Traction Control kicking in? the thing that gets me is usally when i gun it and burn the tires a bit the light comes on, but not when it shakes. the car is a 98 gt with about 79k on it.

You're getting what is called launch shudder. And it sounds terrible when it happens. It is normally not a traction control system problem but a tranny problem. It has been addressed in a GM technical service bulletin. I've seen the problem a few times.

You'll need to get the tranny scanned with a trans capable scanner and see if DTC P1811 (Maximum Adapt and Long Shift) are stored. It is a class "D" tranny fault and does not trigger the SES light.

The remedy is a normally new pressure control solenoid (PCS) which is located with the valve body.

You're getting what is called launch shudder. And it sounds terrible when it happens. It is normally not a traction control system problem but a tranny problem. It has been addressed in a GM technical service bulletin. I've seen the problem a few times.

You'll need to get the tranny scanned with a trans capable scanner and see if DTC P1811 (Maximum Adapt and Long Shift) are stored. It is a class "D" tranny fault and does not trigger the SES light.

The remedy is a normally new pressure control solenoid (PCS) which is located with the valve body.
And about how much will this cost?? and the problem doesnt seem to happen all the time, and it is just like you said a "shudder". I do seem to rev pretty much at the peak of first and get the 40mpg lag but it stays for like a whole 2 seconds, does that tie in at all?? bad tranny? Man, Bnaylor3400, you are the man to ask when it comes to The GP!

Bnaylor3400,

I have a 99 GTP and when I drive it without the "performance shift" it seems that it hangs for a long time between shifting, and even shakes a little in between gears. Is this the same issue with the PCS? If this is the case, Do you recomend to have it done at the dealer or in a tranny shop? How much :2cents: are we talking??

Thanks again!! :iceslolan

And about how much will this cost?? and the problem doesnt seem to happen all the time, and it is just like you said a "shudder". I do seem to rev pretty much at the peak of first and get the 40mpg lag but it stays for like a whole 2 seconds, does that tie in at all?? bad tranny? Man, Bnaylor3400, you are the man to ask when it comes to The GP!

Bnaylor3400,

I have a 99 GTP and when I drive it without the "performance shift" it seems that it hangs for a long time between shifting, and even shakes a little in between gears. Is this the same issue with the PCS? If this is the case, Do you recomend to have it done at the dealer or in a tranny shop? How much :2cents: are we talking??

Thanks again!! :iceslolan


I've had my GTP for over 8 years and had the launch shudder back in 2002. It was intermittent. It was screwing up my ET at the dragstrip. I had to watch how much gas I turned on. If I feathered it I control control it. It feels like bad wheel hop like rear wheel drives car get and like the car is going to fall apart. It progressed into harsh upshifts. After a lot of research and talking to the Pontiac service manager here he told me about the GM TSB. I got a copy of it. It mentioned the P18XX codes, launch shudder, harsh up shifts or excessively delayed shifts. And the cure was to replace the pressure control solenoid. Due to the bad or sticky PCS the tranny wasn't able to command high line pressure needed when you get it on. I replaced the PCS solenoid and applied a Sonnex valve body kit. It took all day to do the work DIY and I'd recommend taking it to a Pro to do the work. One of our local guys in the GP Club took his to a dealer and they charged him $1100 so I'd shop around and get estimates from a tranny shop.

The solenoid only costs around $50. Most reputable tranny shops will do a PCS job for around $450 - $500 including the part.

BTW - When you go to performance shift the problem is reduced because the PCM commands high line pressure so the line pressure is higher than without performance shift on.

Not an easy or cheap remedy but my tranny has been fine ever since the PCS solenoid was replaced.

Hope the info helps.

Thanks Bob, It sure does....

I know is going to cost some :2cents: , but it needs to be done. It really jerks and shakes in up-shifts. I will shope around, and when I get the best quote, I will let you all know so there is more info about this issue.

Thanks!!!

Thanks Bob, It sure does....

I know is going to cost some :2cents: , but it needs to be done. It really jerks and shakes in up-shifts. I will shop around, and when I get the best quote, I will let you all know so there is more info about this issue.

Thanks!!!

Damn you were right with the price, i found the part for 60$. my neighboor the mechnic I run to for help said he will help me replace it for only 100$, but about how much time are we talking? IS this like a saturday, 24pack of beer project or little longer because i will be doing the work while he tells me what to do so I can be the one giving advice on here one day. well whatever... thanx again