need help with trouble code p0706 on a 96 buick park avenue ultra

[temperingloser]

I have a problem with a shudder when driving 40 mph or higher. I keep checking the history codes with my reader and I keep seeing this fault(P0706). I have replaced the vacuum lines leading to the vacuum actuator on the transmission and it still didnt help. I am pretty sure it has something to do with the transmission but I am not quite sure where to go next or what to look for. There wasnt alot of info on this fault when I searched so I was just wondering if anyone could help me understand this.

Thanks
Nathan

[HotZ28]

DTC P0706 Trans Range Switch Performance
http://www.gearchatter.com/viewtopic9475.php

[temperingloser]

thanks hotz28 I checked it out that was some great info. I still think I might have a problem with my shift solenoids or maybe the vacuum modulator for the TCC but my pocket book is short this week so I wanted to check to make sure the shift solenoids were good before replacing the vacuum modulator because it will cost me a 100 bucks. Just wondering if anyone knew a good place to ohm these solenoids. I couldnt seem to find where these land. My chiltons book really didnt spell it out and I looked to no avail.

thanks
Nathan

[maxwedge]

Checking with an ohmeter will not tell if they are sticking or bad, they are in the trans side cover on the aux. valve body, usually when they fail you get stuck in 3rd as a default or the pwm solenoid cuases hard shifting, a full scan with a special scanner can command and confirm the solenoid functions.

[temperingloser]

I dont have to option to check these solenoids right now just wondering if there was a way to check the vacuum modulator or will I have to check the solenoids first

[maxwedge]

A shudder at above 40 under load can be an igniton problem or even lean mixture, pending codes may help here, the modulator would not cause what you describe.

[temperingloser]

I have no pending missfire codes the only codes it is showing is the following.

P0171 system too lean bank 1
P1406 egr pintle valve position circuit
P0706 trans range switch performance

The egr is the only one that stays when the check engine light comes on the other I keep seeing in the history dtcs I did replace the spark plugs and wires awhile back if I had a problem with them I figured it would throw a pending misfire code but I have yet to see one. This is why I thought the transmission was causing the problem.

[HotZ28]

You might want to try cleaning, or replacing the EGR.

[temperingloser]

Alright after replacing the transmission filter (which it desperatly needed) yesterday I had a chance to drive it for a longer trip. It generally happens when driving at higher speeds and low rpm I am going to pull the plugs when the car cools down because I cant remember what plugs I put in them but I believe it was the ac delco plugs. I changed the wires after I noticed this shudder so I was wondering if the plugs were crap. I am familiar with the shudder it seems to be giving me know. After all when I replaced the plugs it was because one had misfired so I pulled it out and it was completely worn out causing a bad shudder.

[temperingloser]

after replacing the spark plugs with no avail I decided to do the tcc test the chilton book described. When driving about 55 mph I was experiencing a shudder so I tapped the brake and the rpm went up and stopped shuddering then as the rpms drop the shudder would continue. I am sure now that the tcc is the problem but I am not quite sure where to begin. I was just wondering if it is a common problem for the vacuum actuator to act up or will I have to pull the transmission apart to replace the solenoid or I will I have to replace the tcc. When I replaced the transmission filter the magnet was full of fine gray stuff and the whole bottom of the pan. I guess this suggests something maybe the clutch wearing but I am not sure. any additional info to try to correct this would be appreciated.

[maxwedge]

Again, most lean or ign misfires occur in lock up as this loads the engine, when disabling the tcc most misfires go away, so eliminate any chance of this before blaming the trans. Also if the tcc is slipping this will show on a scanner.

[HotZ28]

You are on a wild goose chase! You said that you have an active P1406 EGR pintle valve position circuit code, which can replicate the low rpm O/D shudder issue you described. Have you cleaned, or replaced the EGR?

[temperingloser]

Cleaned but did not replace egr and no more egr faults at this time. I am still looking into this issue. I have tried a couple of things that I will post as soon as I know the results

[temperingloser]

Alright after looking around a bit I noticed one of the mounting bolts for the ecm was missing. Could this cause the shaking I described earlier if the ecm is shaking. After noticing this I wanted to see if it would move with me trying to pull up and down on it and it did. Any help would be appreciated.