2nd Gen Non-Engine/Transmission 97 auto to G56 swap, ABS light on and no speedo

[Rick Harper]

Working through a few bugs after my swap.



The ABS and Brake light are on all the time. I cannot get the truck to give me the code, so I am not sure why.



Also, the speedo will not work. The dakota digital interface that takes the ABS signal and converts to the speedo signal has power, and the diagnotic light flashes when the truck is moving indicating it sees pulses coming from the ABS circuit, but there is no output going to the speedo. I disconnected the input from the ABS, but the lights are still on.



So, is there another circuit somewhere that I interuppted when the auto was removed?



Ricky

 

[GAmes]

I hate just throwing parts at a problem, but the ABS light and the speedo have two things in common, the ABS sensor in the differential. If you have confirmed there are no breaks in the wires it sounds like you have a bad sensor. If you lived closer you could try mine, I have a spare.

 

[Road Dog]

There's a speed sensor on the transmission too (used for shifting) and it provided a signal for the speedo up to some year and then the ABS sensor was used for speed. The second thing is a typical code reader only reads the engine (PCM or ECM) module, not the others like the ABS module. You need a proper scan tool for those.

 

[GAmes]

There's a speed sensor on the transmission too (used for shifting) and it provided a signal for the speedo up to some year and then the ABS sensor was used for speed. The second thing is a typical code reader only reads the engine (PCM or ECM) module, not the others like the ABS module. You need a proper scan tool for those.

RD, I know you are trying to be helpful but you didn't read the OPs post. He went to a G56 manual transmission from the stock auto. The speed sensor that was on his auto is gone, so it cannot provide a signal to the speedo. Many of us who converted to the G56 use the ABS sender in the differential to power our speedos by using a Dakota Digital interface. Mine has been working for nearly 50k miles so far.

 

[LVJUNIOR]

I chased a ghost similar to this on a freinds truck and found a broken wire under the dash. there is a bus connector under the dash that has a bunch of (if i remember right white and purple) wires going to it from the PCM this provides a low voltage positive signal to all of the data circuits. If the main input wire is broken it can kill the entire dash but if a couple of wires are loose or broken it will be only a few items malfunctioning. 20% chance that is the problem but it is free to check