1994 Grand Prix ABS light and obd1

[jrappl]

I just acquired a 1994 Grand Prix 3.1L with 61K miles on it from a friend.

It has been off the road for 5-6 years but was being driven on site every month or so until a year ago when the right rear brake line broke, it's been sitting since.  When I got it the master cylinder was empty/dry and of course the brake and ABS lights were on.  I was told the ABS light was not on until the line broke and the fluid leaked out.

I have replaced both rear lines and bled the hydraulic unit and all 4 wheels.  I have a decent brake pedal, the brakes work and the car stops fine - quick and straight.  The problem is the ABS light is on solid.  I've done some research and this means the system has disabled the ABS.  I think it has latched the error from the low fluid condition and won't re-enable the system until the error code has been cleared.  I've tried to clear it by disconnecting the battery and discharging the system without any luck.  The ABS light never goes off, it is on solid from the time you turn the key on, it does not blink.

This is a 1994, it has the 12 pin ALDL connector and the under hood label says "OBD1 Certified".  The 12 pin connector only has 3 wires in it, it DOES NOT have the diagnostic pin to display codes on the dash.

Is there an inexpensive way to read and clear the ABS code or do I need a scan tool?  Is there anyone in the Research Triangle area of NC (Raleigh/Durham) that has a scanner with the correct cartridges for a 1994 gm obd1 ABS system that would be willing to do it?

Thanks.

[Professur]

Have you looked for the Factory Service Manual for this car?  And are you sure it's not just the light is shorted on?

 

The Snap on Mt-2500 scantool can be had on ebay for under $100 regularly. Nice older tool to have. Might be your ticket.

[Frosty]

GE or Guitarsextreme lives in the Charlotte area. I think we have other members that live closer to Raleigh.

[jrappl]

I don't have the service manuals as I just got this car.  I'm looking for a scanner, either the mt2500 or an OTC 4000E.  I've seen some for sale but hard to find ones under $100, any of those seem to be just the scanner without any cables or cartridges or they are being sold "as is" untested, no return.  I can't spend $100 for a paperweight.  It's also hard to spend much more on a scanner that will get very limited use.

Can someone give me some info on the scanners?  I have seen some references that imply that you need a specific ABS cartridge in addition to the engine cartridge?  Anybody know if that is right?  Will any GM cartridge 1994 or newer handle my obd1 GP, all systems including ABS?  What are the keys for and would I need the correct key also?   

[Professur]

The keys are for the OBD2. A 'domestic' cartridge for the MT-2500 should be all you need. If you've done all the rest of the work to get the system working, it might be worth the time to just take the car to a specialist and have them check the ABS with their professional equipment. When you're talking old cars to old grey haired mechanics, they tend to get nostalgic. My local guy is more than happy to discuss my old cars issues and how to sort them at home ... when I'm in paying him for some work on one of the newer ones. I've even once paid him half an hour of rack time just to talk through a job with me. Just be up front and don't waste their time and you're usually good. He knows I'm usually only there for a diagnosis on the old girls. I let him deal with the new crap cars, and things like tires that take special equipment. A steering knuckle that wouldn't fit in my oven to bake went to him for a torch and press. From the marks the press left on the hub, I saved myself a lot of wasted effort there. No way was I getting that sucker loose at home. Aluminum and steel ... what farking idiot thought that was a good idea?

 

[jrappl]

Making some progress...  Got a scanner today and pulled ABS codes - shorted/open left front wheel speed sensor (25).  I pulled the sensor and it tests as an open circuit.  I'll replace it and hopefully I'll be on to the next problem.  Cars don't like to sit...

Thanks for the help!

[Professur]

Which scanner did you get? On cars with electronics, a good scanner is a must. There's simply no way to debug these things without one.My MT2500 was bought to check the trans for my old '93 grand caravan. Paid for itself in it's first and only use. Told me to walk away, and I did. Mine came with the OBD2 dongle, but no keys, and no cartridge. I'm told there's code for it all the way up to 2009.

Edited January 26, 2017 by Professur

[jrappl]

I got a used Solus Pro for just a little more than the mt2500s were selling for.  It came with the battery and charger, the obd2 adapter with a good selection of keys and a few obd1 adapter including the GM-1 I needed.

It's nice and easy to use but it does a lot so I will be reading the manual when I get a chance.  Software is stored in internal memory so no cartridges to mess with.  Mine is updated to 2011.  Snap-On sells upgrades to current models (2016 is latest so far) but the upgrade is very expensive.

 

[Professur]

yeah ... but so worth it when you need it. The Solus is a solid machine .. you'll get a lot of  use out of it. Probably far more than you ever want to once your friends find out you have it. Almost as bad as owning a truck when moving day rolls around.

[jrappl]

It's new and cool right now so I don't mind helping out...  On the truck thing, yeah been doing that for 40+ years...