I need some help.....

[bow61509]

Ok ive got a 1993 454 tbi with a 4l80e from what i understand. The problem is the other day on my way to work i hit a small pothole. And ever since the speedometer has stopped working, and i suppose its now in limp mode. I pulled the codes and only got code 24 which seems to be the code for the vss, now today i changed the vss and nothing has changed, i even unhooked the battery in hopes of clearing it. So where do i go from here? Upon visual inspection of all the wiring i can get to it all appears to be fine. Im just totally lost here. Is there anything else that controls this or is there something else at play?

Sent from the big block!

 

[98chevyz71]

What does limp mode do?

 

[great white]

I'd say you're jarred something loose with the impact.

Your DRAC is integral to the cluster on a 90 IIRC. Make sure the plug in the back of the cluster is still all the way in....

*edit*

Crap, it's a 93, not a 90.

Have a look at your DRAC module. It's in behind the glove box with the ECM. You can also check your cluster to see if it's loose.

 

[bow61509]

Would the drac module not be letting the signal from the vss into the ecm causing the problem?


And thomas my truck is currently staying in first gear

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[bow61509]

Also i should add that the truck is just staying in first. It wont shift up,

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[bow61509]

When i first got the truck none of the gauges worked and it turned out to be the fuse for the cluster. Now since its replaced everything was working up until this happened except now the speedometer and the transmission not shifting. Also i forgot to mention the abs light is on. Which is all the same symptoms i had when the vss went out in my 96. Im just totally lost at this point. Im wandering what all the speed signal goes through between the vss and ecm. Great white i just went out and looked at the drac both connections are tight and it looks fine. One other thing though is that i have much smaller tires than factory and my speedo has always been off because of this. Is it possible the drac itself has gone bad?

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[bow61509]

Ok just did a little googling and found a person with the exact same problems. And an answer! The fuse labeled brake was popped. Seriously thats all it was went out and checked my truck and behold the brake fuse was popped, replaced 10 cent fuse and now speedo is back to "working" trans is shifting and abs light is gone. So for you 4l80e guys apparently the brake fuse is important to the trans working correctly, my only question in this is why?



Oh and great white i saw a post from you about adding dip switches to the drac/vssb to make it adjustable how can i get my hands on one of those?

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[great white]

The DRAC and a 93 takes the signal from the VSS and converts it to the right PPM for the ECM speedometer and the cruise control. The track is what also holds the calibration for your gearing and tire size.

You either have to move the wire jumpers in the Drach, or you have to install dip switches like I did. The dip switches act just like opened or closed jumpers.

You can either remove the jumpers and solder in the dip switches, or if you want to flip the bill you can send them to me and I will do it for you. No charge other than shipping the DRAC and the dip switches. If you want to chuck in a couple bucks for solder and my time, that's up to you.

I do this on a "gratis" basis, so it's best if you run to the scrap yard, pick up a spare DRAC and send that to me. Dip switches used to be available at RadioShack, if not there then they're super cheap on eBay.

Also, I'm not a business. Just a guy tinkering in his own 2 car garage, so it may take a while to turn it around.

 

[bow61509]

Hey that all sounds great to me will any drac unit from a 93 work or do i need to find one out of the same style truck i.e. 454 auto etc. Or just any of them from a 93. I may try my hand at it first but im not the best at soldering can just do enough to get by lol. Do you actually have a how to thread on doing it? I couldnt remember just saw it one time

Sent from the big block!

 

[95C1500]

http://www.tbichips.com/drac/