Vortec 454 DTC codes

[markeheiden]

Howdy all, I put a 96 454 Vortec and 4L80E into my 82' suburban. Not for the faint of heart. Anyway I have 4 DTC codes and need to know if any are a problem for the long term if ignored.
1. The Torque Converter Clutch is semi-auto now and so I get a P0719 code from that.
2. The EGR Tube wouldn't clear the firewall so I plugged the sumbitch and I get a P0401 code for that.
3. I used a high flow cat and I get P0420 and 430 codes for that.
It runs like a banshee, mileage isn't great but am wondering if it could be better. Any suggestions?

Thanks

[Keith@HPTuners]

Can you elaborate more on how your TCC is "semi-auto"?

The other codes won't hurt your performance, just cause you the annoying SES light. Having that SES light lit up all the time could cause you to miss a new DTC being set that might be very important.

[markeheiden]

Thanks for the reply Magnus. I connected the TCC to a switch on the dashboard that puts voltage on the TCC when the switch is on. I ran the circuit thru the brake pedal switch so it disengages when I come to a stop. The difference is, I control when the lockup is in or out NOT the computer. This way I can lock it up in high gear and it won't unlock if I want to run WOT in high and also, I can keep it from locking up under certain conditions.
Since I now know the other codes won't cause a long term deficiency in performance, I need to figure out how to fool the computer into thinking everything is fine and turn off the SES light. That's my next challenge.

MH

[Keith@HPTuners]

Be very careful with manual lockup. The TCC is not meant to be locked up at WOT nor was it meant to be locked up manually. It's good that you put a switch on the brake for it to disable then.

If you put too much stress on the TCC and it shatters or starts to flake it will send pieces into your trans pump and throughout you trans, thus trashing your transmission and requiring you to get a rebuild.

If you are constantly locking it up under heavy power/WOT, chances are it won't last too long.. Even the aftermarket converters with stronger clutch material I wouldn't lock up too often at WOT.

Use that switch carefully.

[markeheiden]

I have a pretty good idea when to use it and when not. The worst case is under heavy load, low gears with the motor in its peak torque area (around 2800 rpm). Once the motor is at higher rpm in higher gears however (say above 3,800 and up) there is a lot less torque available to be applied to the tcc. I don't use it until it's in 4th gear and that is a lot less abusive than the factory setup that will engage it in 2,3, and 4. Best case is obviously at cruise where it is used for increasing both mileage and lowering transmission temp. I've been controlling it myself for over two years now and it works perfect. When I let anyone else drive it, I tell them to leave the switch alone.

Any ideas on how to fool the computer into thinking the egr, cat and brake switch are operating normally?

Thanks again,

MH

[kdbell]

Mark, would you share your wiring diagram with me?
I am really only interested in disableing the TCC while towing in the hills. It robs too much torque causing frequent downshifts; but, I am intrigued by the ability to also lock it "on" and still be able to apply throttle.
I am using a 99 SilveradoC2500 with nearly stock 6.0L and upgraded E rated tires which are 1" taller than stock.

Thanks
Kenn Campbell

[12secSS]

All of this TCC can be easily tuned into the ECM. There is no need to have a manual switch. The TCC is not engaged in 2nd, 3rd and 4th ... but rather if you place the gear selector in those positions it will engage. The TCC lock up and release tables are very easy to tune to function exactly how you would like ... this removes the constant fear of paying attention to a lock-up switch, and paying more attention to driving and what is around you when towing. Our trucks have a dual trans mode setting (Tow/Haul mode) so you can accomplish this more easily, and not affect daily driving. Just an FYI.

[markeheiden]

kdbell, I just looked at the circuit on the OEM service manual and interrupted the wire on it's way to the brake pedal with a switch on the dash. This is probably why I have a DTC code for the TCC.

12secSS may be right, all this may be "programmable" with the ECM, but if you are not an ECM programmer guy, it can be done with simple wiring. Also, the transmission doesn't get confused by the ECM trying to calculate the conditions and give you the right gear or lock up condition. There is no "tow haul" mode on my truck. The motor and trans came out of a 96' dually and it is in an 82 body.

When the motor lugs on a grade for example, I can unlock it instantly putting the motor back into the power band, and if I want lock the converter in third gear for example for a long pull, I can do it, reducing transmission heat dramatically. When the converter is unlocked under load for long pulls, the heat in the transmission builds fast. I can watch the temp lower on a grade after locking up the converter.

I have been running it now for a couple years like this and it has worked fine. (see orig. post date) I dont have a problem paying attention while towing and I have no fear of my switch. It's an automatic, there's nothing else to do while driving! ;D