i have an 00GT with 103K miles. A week ago i installed the ZZP PCM and took a 300+ mile trip today. When i got close to home i noticed it whining under acceleration and doing hard shifts. Got home let it cool down and drive it again. Did fine until it got warmed up and started doing itagain. I get no error codes on the dash. Is this the solenoid issue?

It could be the PCS solenoid. A scan wth a trans capable scanner may show a DTC of P1811. This DTC would corroborate a PCS problem. It is stored but does typically not trigger the SES/CEL light. A re-programmed PCM may amplify a PCS problem.

i stuck the OEM PCM back in and didnt have the issue so far. Gonna drive it around more this afternoon to see. The tranny did fine the past week with ZZP PCM in. Who has these Tranny scanners? autozone, advanced auto, Oriellys??

Re-programmed PCMs modify shift points and increase line pressure. The PCS helps controls line pressure. The whining and hard shifts is probably because the line pressure is too high.

Not all odb-ii scanners can read tranny codes, especially the generic variety. A scan tool like a GM Tech II or Snap On MT2500 and the better scanners like Actron Super Scanner can detect these codes because they have GM extended code programming. The average tranny shop can scan for codes. Some Autozones may use the Superscanners but not all.

Does your model have performance shift?

i have a scanner but not for the extended codes. Why would it now just whine? you would of thought it would of started soon after i installed the PCM. Should i contact ZZP? Yes i have the performance shift, On GTs its ;always on; as they said.

PCS problems show up when the trans gets warm. The new calibrations in the PCM have changed so the PCS is more than likely working more now to achieve higher pressure and as it strokes it becomes stuck at the higher pressure. I heard of some people going to AutoZone and getting some trans codes. Just don't tell them your looking for trans codes say engine problem. If you give the OEM PCM sometime to recalibrate it might do it also.

im gonna drive back home this afternoon with the OEM pcm to see, its about 25 miles so i will find out for sure. What sucks is that if the tranny doesnt do this with the OEM pcm then the ZZP PCM is a waste but if i keep the ZZP PCM then i will spend big bucks in getting the PCS replaced.

Well you need the PCS replaced more than likely anyway

not once did the tranny act up on the way home, i drove it hard too.

It is possible the issue is just the ZZP PCM but that puts you in a weird predicament. Looks like for the time being you are stuck with the stock PCM which really bites. But to get the matter resolved to your satisfaction sounds like it will be real hassle. Maybe you have an idiosyncracy type problem related to the programming ZZP uses. I have not heard of any problems with ZZP units but to the best of my recollection you are probably the only member that has one done by them. I went with DHP the first time around and then a custom programmed Intense. Maybe you should check with ZZP tech support and see what they say. Good luck.

BTW - Didn't you get the PCM which now has the ZZP programming off of EBay or something? There may be a hardware issue with it.

Yeah i bought a stock PCM off a person from another site that was planning on using it for a reprogramed PCM but went in another direction so i bought it. Day 2 and no hard shifts or whining. Im gonna stick the ZZP back in before going home to see. What i dont understand is why a week and half later it starts doing it? I will email ZZP to see what they say.

well i swapped the ZZPPCM back in before leaving work, not once did it hard shift or whine. Now does this make sense? NO

You said that you took a 300 mile trip do that trip all over again with the OEM PCM and I bet you get the same thing. I bet your PCS is starting to go south on you

maybe, but i guess i am gonna check around and see whatthe cost is to replace the PCS

well when i stuck the stock PCM in there for the 2 days, it didnt hard shift or whine so i reinstalled the ZZP pcm and did from thursday afternoon till today on the way home when it started whining and hard shifting. Why is it taking days to start back up?

how many days did you run the OEM PCM? Its kind of odd that it seems to only do it with the ZZP PCM.

i ran the stock pcm for 2 days and the ZZP for 3 days.

i had the same whining and hard shifting issue in my 2000 SE, 3.1. i was told by a co-worker to try "Lube Gard", red bottle available at NAPA. so far the issue has resolved itself. though this is just a temporary fix. also, i had a rough idle and slow acceleration. i read on AF to try something called "Seafoam" so i did and the rough idle is gone and accelleration is BACK BABY!!! thanks to the AF community for their help.

after doing more testing. i found out that when the ZZPpcm is installed, the whining hardshift will start about 200 miles after its installed. I went back to the stock pcm and drove it for over 200 miles and never did it once. I now have the ZZP back in to see if it will start it again at the 200 mile mark. ZZP said they could tune down the shifts to see if that would help.

after doing more testing. i found out that when the ZZPpcm is installed, the whining hardshift will start about 200 miles after its installed. I went back to the stock pcm and drove it for over 200 miles and never did it once. I now have the ZZP back in to see if it will start it again at the 200 mile mark. ZZP said they could tune down the shifts to see if that would help.


that might help but youll prob still get the same whining and harder shifts after 200 miles. i personaly dont put any additives in my car not even fuel injector cleaner. all additives do are just cover ups for problems. when the additive wears off the promblem comes back and uualy worse.

whats addiitives gotta do with it?

When this thing starts whining and shifting hard buzz by autozone or any place that scans & get it scanned look for a p1811.

i have a regular scanner and show nothing cause there is no engine light that comes on.

i have a regular scanner and show nothing cause there is no engine light that comes on.

You'll need a scan tool capable of reading GM extended DTCs or better known as a trans capable scanner. The P1811 is stored and does not give a SES light.

What did ZZP say? Sounds like the programming for the PCS solenoid control current can be lowered.

while driving to work this morning, i was reaching the 200 mile mark and at 190 miles it started shifting hard. ZZP said they could tone down the shifts so hoping that will do it cause i really want the ZZP PCM.

update:

i sent the pcm back to zzp for adjustments. he lowered line pressure to pretty much stock and it still whines/shifts hard at the 200 mile mark and after. im lost here. here is the last adjustment on the pcm:
New PCM has torque management put back in, line pressure is stock except for WOT, shift time is stock.