Engine/Transmission (1998.5 - 2002) Lock up switch and codeP0743

[BigDan]

I have a DTT transmission and I just instaled a Lock-up/Mystery switch. I followed the directions on the TST page http://www.tstproducts.com/tranny_install.html



And now I showing this code P0743(TCC Solenoid/Trans Relay Circuits) and it wont go away. The switch works just fine, its just my engine light is always on now, even after my mechanic reset it.



Does anybody know whats going on and if this is normal, and how can I fix it??



Thanks

 

[snowracer69]

you did put the jumper in, correct? And you're not trying to run an LED off the switch or anything else and backfeeding power into the PCM, are you? Just a couple of the things I've seen happen before.

 

[BigDan]

Yes Im running a jumper in place of the trans relay and have power across both poles. I am not running a Led or a lighted switch, just a plain 2 pole push button on/off switch. .

 

[RCone]

The code will go away if you pull your jumper and put the relay back in. Same happened to me. I don't know exactly what purpose you are using your "mystery" switch for, but mine was for drag racing. Other than that, I don't use it because of the problem you describe. Even after replacing the relay, things will not be exactly the same till the code gets cleared (for me on an 01 like 7 starts) and by not exactly the same I mean like normal TC lockup etc when it is supposed to. If you are using the switch because you have an exhaust brake, I would say don't. Use an Autoloc or Smart controller or another device like that, not the mystery switch.



Roger

 

[BigDan]

Its mainly for Drag Racing. And if thats the only cure... . Thats lame...

 

[JPereira]

Anyone know if this mystery switch will work on a 4. 5? I am interested in this for Dyno and possible Drag racing. I am goiing to try and read the Mopar manual but was hoping someone with a 4. 5 may have already done this.



Thanks, Jeff

 

[1FSTDSL]

I have seen it set codes on California trucks, you will have to pull the jumper wire to get it to go away. That is how I found out my truck was a CA truck, but it was purchased new in AZ.

 

[RCone]

1FSTDSL, I think you may be onto something there with regard to a CARB truck. Only by going thru the process of installing the CaTCHER ECM did I discover that even tho I purchased my truck in Oregon, is was a CARB (California) truck. Although as we know now there are other states back east that sell the CARB version. That my explain the code thing with the TST method of the mystery switch. We need to hear from others that have the switch and whether they have experienced problems and try to find out if the fact that it is a CARB truck is the common denominator.



Also, I won't be using the mystery switch anytime soon. BigDan, I don't know if you've spoken to BillK on this issue but I know for a fact that he doesn't like them as it is to hard on the drive train. Some have claimed that they picked up 4 tenths in the 1320 and I only saw about 1 tenth gain although that could be just be me the drivers fault. So my opinion is that, it isn't worth it. There is another use for it but this post is becoming to long already.



Roger

 

[snowracer69]

Bill told me he likes people to lockup in 3rd, but I plan on doing it in second. He said there will be no problem, but it is a hard shift.



How, besides the code setting thing, do I find out if I have a CARB pickup? Mine was bought new in Portland, Oregon, but that doesn't mean anything.



Josh



p. s. my lockup switch (already installed, just not tapped into the wire) will be tapped saturday after getting my next round of transmission upgrades done. Also will be hooking up an overdrive switch.

 

[1FSTDSL]

When you hook it up to a scanner it will tell you if it is a CARB truck.

 

[snowracer69]

When you hook it up to a scanner it will tell you if it is a CARB truck.

Won't be doing that anytime soon, so I guess I just won't know till I hook up the jumper in the relay.

 

[RCone]

Look at the driver side front of engine. On the metal label it should say EPA and Carb. If the are a series of 3 numbers under the EPA column then you have a Federal truck. If there is one number under the CARB column or in my case the rivet might have covered that number up it is a CARB (California and some other eastern states) emissions truck. Clear as mud huh?



With regard to the lockup switch, I chickened out and never threw it till I hit 3rd gear just like Bill said. There are others that throw the switch as soon as they hit 2nd, maybe that's why I only gained 1 tenth second. Do remember a couple of things tho after crossing the 1/4 mile line, shift into neutral, disengage lock up switch and 4HI if you hadn't already done so as soon as you shifted into 2nd on acceleration. If you don't disengage lockup switch, your transmission ain't gonna like you very much on decelleration at that speed and if you don't disengage as you turn off of track and onto frontage road, you may stall and that looks stoopid!!!!!

 

[snowracer69]

I've spent HOURS on the phone w/ people who've been running theirs down the track picking minds about proper techniques for racing these things. I plan to launch in 4x4 at about 15 psi (maybe 20, we'll see on the 60 ft times), lockup and shift out of 4x4 in second, soon as hit third I'll throw my OD switch. Upon crossing finish line, both switches go off, brakes on hard, and coast to the end. Taht's the plan at least... no gurantees it'll work that way. Pic of lockup and od switches:



#ad

 

[RCone]

why the OD switch? Mine is in the stock location and I just leave it on when I launch. Just one less thing to worry about at the end. Also, not remembering your sig, I assume you have billet input and output???? If you don't 15psi is to much to launch with and don't forget you also have an intermediate shaft that people have broken.

 

[snowracer69]

od switch is not the regular od switch! The way it was explained to me is that it's a "forced" od switch that causes the process of preparing for OD to start earlier... ie, no hesitation at the top of 3rd gear to fill the piston (? not sure if htat is exactly what happens or not). It's installed the same way the lockup switch is, by grounding out a wire on teh pcm (I don't know which one) and the same relay jumper is associated, so no worries there.



Billet shafts go in Saturday (basically new transmission). Intermediate, as far as I've found, has only been broke by Opie, when they were launching at 45+ psi and just flogging his transmission trying to break the new style output shaft. Bill says no worries on mine unless I do something dumb. Am waiting to hook up switches till saturday when Fred and I do all the new transmission stuff.

 

[GFrance]

I have the same thing Roger. Didn't know I had a calif truck until we got the smart lock in. I just put a little DTT sticker that Bill gave me over the check engine light. LOL Works for me.

 

[RCone]

Actually, that's a pretty neat idea putting a sticker of the chk eng lite.



Congrats Snow on getting your transmission upgraded. Yes, I saw Opies intermediate shaft laying on BillK's workbench and you may be right as to he being the only one we have heard of but I would bet that there are more that we haven't heard of. Don't know about Maddog but he's just about broken everything several times. With regard to the preparatory OD lockup, that would be a new one on me. Let me know how/if it works.



Regards,



Roger

 

[snowracer69]

I know that it works... Fred's been telling me to do it for 2 years and Bill said "yep, all the go-fast people put them in... just saves on the pause at the top end of third. " To prove it, go out and mash on the go pedal w/ OD switch in the on position (so it will shift into 4th). Hold it to the floor as you would when running it down the 1/4 and see just how long it waits on the 3-4 shift... there is quite a pause. Not supposed to be w/ the od switch. Time will tell though.



Oh, checked my plate for the CARB vs epa... no numbers under EITHER... so I guess mine is just extra special.



I've had my DTT done for 2 years now w/ 35k perfect miles... just decided to finish her off and get the new parts so I can run it down the track(s).

 

[Snow man]

snowracer, I broke an intermediate shaft ,almost 40psi,trying to break opies output shaft. I now have all of opies shafts. I dont plan on breaking any of them. I have both switches in my truck too. your plan is perfect,ive been using that technique drag racing for yrs. The 4th gr switch is needed with trucks with 4. 10s and big power,if your not runnign DTTs new race VB. That VB has a perfect WOT. 3-4 even in my truck.

 

[snowracer69]

will see Saturday just what vb mods are being done... . i don't know just yet.