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94 Chevy sport van g30
Van was parked for a year and now it won’t shift. I found this computer module for the speed sensors under the mat by the break pedal. I don’t know what it’s called or if I can buy it new, I’ll attach a picture. I have a scanner and it won’t power on to the obd1. I have tried to use a jumper to read the codes but that don’t work either, the engine light never flashes. Also, where the throttle cable connects, there is another cable going under and forwards the tranny, it connects to a black box with wires and a vacuum line.
Last edited by mountainmanjoe; Dec 3, 2022 at 10:36 PM.
94 Chevy sport van g30
I don’t know what it’s called or if I can buy it new
Well, when you input the numbers on the part in your photo (16132857A or 16159135) into an web search, it comes up as "Vehicle Speed Sensor Buffer"
There's a whole page about it here: 1989-1995 GM External VSSB/DRAC Modules
A bunch of parts for sale come up too. It's unlikely you're gonna find an 28yo OEM part new, though.
Originally Posted by 5rrabon
there is another cable going under and forwards the tranny,
You did turn the key on when you jumped the connector, right? Did we check the fuses for the ECM?
Most scan tools available now have no provision to even read OBD1 or connect to it.
This van has a 4L60E or 4L80E transmission, shifting is controlled by the ECM, the vehicle computer.
If you're not getting any response from the ECM, it could be that is damaged or bad, although given they put them under the driver's seat it's not highly likely, it's still easy to inspect it visually.
The 4L60E does not have a TV cable. The second cable may be the cruise control if equipped, but these use a cable for the transmission shifter also which could be what you see. That cable does not connect to anything else.
This response may be a day late and a dollar short, but here goes: This definitely appears to be a DRAC module. I've got one on my 1993 G30 RV chassis, and have replaced them several times. These can be purchased as a remanufactured part. I'd avoid UD Module as the part is fairly expensive ($150 +/- with shipping), they only have a 30-day warranty, and, in my experience, their customer service is poor with no phone contact; you can only order the part through their online web page. Whatever direction you may go or have already gone, it's best to order the part as a calibrated remanufactured DRAC, which takes into consideration your tire size and rear end gear ratio; otherwise, if not custom calibrated, your speedo can be significantly off.
Originally Posted by 5rrabon
94 Chevy sport van g30
Van was parked for a year and now it won’t shift. I found this computer module for the speed sensors under the mat by the break pedal. I don’t know what it’s called or if I can buy it new, I’ll attach a picture. I have a scanner and it won’t power on to the obd1. I have tried to use a jumper to read the codes but that don’t work either, the engine light never flashes. Also, where the throttle cable connects, there is another cable going under and forwards the tranny, it connects to a black box with wires and a vacuum line.
Last edited by paulmc; Nov 12, 2024 at 10:05 AM.
Reason: Added info
Additionally, what I don't know is if some company produces a modern upgrade for a DRAC setup. It's archaic and if the module fails, you get stuck in a gear, and it won't change. However, it's a plug and play part, and if you have a working spare, you plug it in, and the trans will typically shift properly and off you go again.
Transmission won't shift
