1994 Volvo 850 ABS light on

[lorant]

Hey.
I have bought an 850 with the abs light on, and it went out once driving off road and then when returned to hwy it came on again and its been on since, checked the fuses, cleaned all abs sensors, they all have 1140-1500 ohm resistance, i have the tevis 4 pump not the newer one. Light still on. I dont know where to go from here.
Some say change the ignition switch. ?!
When i turn the key on it flickers really fast 4 times. trac dosent work either, abs same.
Any clues or ideas?
Can it be a broken solder on the abs control unit?
This unit i looked at it but its not what is Matt was talking about this is old school tevis.
Thanks guys its past 1 am here going to bed.

[Ozark Lee]

Welcome to MVS,

Since you have a '94 you can read the diagnostic codes yourself. You have an on board diagnostic system built into the car.

You need to read the codes from port A-3 and post them back.

Here is how to read codes - it is specific to the ECU which is port A-2 but it works just the same for port A-3.

http://volvospeed.com/CheckEngine.php

...Lee

[lorant]

Hey.
so the code that flashed out is 124, 214 314, 324, which indicated the right rear abs sensor. i have compared the resistance with the left side and resistance is very close. Could it be still bad? Do I have any other options? As I am licensed tech, i ususally dont work on volvo, but all other brands, this is my own car, and one shop told me where i got some tires that dosent matter what goes wrong with the abs system it always pops these codes regardless if its the right front it will still flash right rear. Is that true? Dosent make sence.
Thanks

[Ozark Lee]

The 3-1-4 code would cause all of the others. Check the wiring between the connector on the sensor and the module. It is the twisted pair that has Green/White and Green/Black wires.

The schematics I have show the Green/White going to pin 45 and the Green/Black going to pin 27 on the module connector.

...Lee