1993 850GLT Changing out ABS module?

Georgia · Post by **Georgia** » 16 Sep 2009, 07:11

I have all of the symptoms of the ABS module being bad in my car. Odometer, trip-ometer, and cruise control do not work. Also, TRACS and ABS lights are on most of the time (intermittently). Is it as easy to change out as I think it is? It's sitting right on top of the engine and looks relatively easy to remove and replace but I want to make sure there are no "gotchas". Can someone tell me specifically how to remove and replace it? Also, tell me if you think I need to do anything before I jump to replacement.

Thanks!

FCPEURO · Post by **FCPEURO** » 16 Sep 2009, 07:55

I would check your codes before you just swap the ABS controller. The ABS units on the 93 - 95 850s are much better then the 96 -97 model and don't go out very often.

Georgia · Post by **Georgia** » 16 Sep 2009, 08:05

Can you tell me which Diag port and socket I would use?

Post by **Ozark Lee** » 16 Sep 2009, 10:00

Port A-3 for the ABS and port B-2 for the cruise control.

There are great diagnostic tests for the cruise control in the manual. If you have not yet downloaded it it can be had from here.

https://www.matthewsvolvosite.com/downlo ... vo_850.zip

It is for a '95 but it is 99% compatible with your '93.

...Lee

Georgia · Post by **Georgia** » 16 Sep 2009, 10:33

Okay, I'll check it out and post DCTs shortly.

You guys are the absolute best!!!!!!!!!!!!!!! I mean it! EVER!!!

Georgia · Post by **Georgia** » 16 Sep 2009, 12:08

Okay, here are the DTCs that I received from those sockets:
A3=
4-4-4
3-1-1
3-2-1
2-1-1
2-1-2
2-1-3
2-1-4
1-2-1

B2=
1-2-2

Post by **Ozark Lee** » 16 Sep 2009, 14:29

Most of the codes are wheel sensor related and likely indicate that the reluctance rings on the axles a plugged up with crud. The reluctance rings look a lot like a gear with 48 teeth.

The rings are kinda tucked in behind the steering knuckle on the fronts. You can use about anything to clean them, electrical contact cleaner, carb cleaner, brake cleaner - any solvent will do. Some people freak out over using brake cleaner but I have never had any ill effects.

On the rears it is a bit tougher since you need to remove brake drum / rotor to get to it. I did a writeup on replacing parking brake shoes that shows the reluctance ring in detail here:

https://www.matthewsvolvosite.com/forums ... 428#p26428

The third picture shows the ring fairly well - in its dirty state.

The 4-4-4 code could be a problem. Try clearing the codes and see which ones come back.

The 1-2-2 code on the cruise only means that the car is not moving over 22 mph while you are testing. Go through the testing procedures in the manual to verify the various cruise control functions. It helps to have an assistant that can press buttons and the brake pedal as you read the codes.

I didn't really address your odometer problem earlier. The gears inside of the instrument cluster are broken. It happens to all of them.

Details on how to fix the odometer are here:

https://www.matthewsvolvosite.com/odometer_fix.php

There is a ton more information if you click on the Comment on this odometer fix procedure link.

You can get the gears from www.odometergears.com or from IPD or FCP Groton.

...Lee