I have a 92 Volvo 740. Since I got it, I've been, little by little, trying to fix everything. One of the panel lights that's also turned on is the ABS light. I read someplace that the OBD port to check any ABS issue is the port 2 on the "B" thingy on the engine compartment. The moment I stick the prong in, the light is solid. No flashing whatsoever. This was done while the car was turned off. Also, I read that to check the ABS codes, the car was supposed to be checked while still on and after riding it above 35 mph. I did this and the light is still solid. No flashing. I know the brakes are OK. I've cleaned the sensors on the front wheels. Yes, they were a bit dirty but got cleaned. Also, I replaced the 2 relays under the ABS cover next to the pump. Any idea what I'm missing?

 

with the car off there should be nothing powered at the diagnostic box. leads me to suspect your ABS controller, which is under the drivers seat, is fried.

 

Would the ABS Controller from a 93 960 fit mine? And I guess I will have to remove the driver's seat to get access to it, right?

 

The SRS is under the seat, not the ABS...

1992+ Cars With Underhood Diagnostic Units. To retrieve any ABS diagnostic codes which are stored and are noted by a lit "ABS" lamp, turn the ignition switch on to KPII and leave the engine off. Look under the hood to locate the Diagnostic Link Connector boxes. Your car can have one box ("A") or two ("A" and "B", 1992+). The "A" box has the diagnostic connector pigtail, the test button, and the LED readout lamp.
Put the Diagnostic Link Connector probe into Box A, Position 3. Push button on DLC for >1sec. and capture codes flashing in the red lamp.
To clear codes, place the DLC probe into position 3. Hold DLC button down for >5secs. Release for 3 secs, then press again for >5 secs. This will clear the codes.

 

So, back to square one. I've checked the box "A" port 3. I pressed the button and although the light lights momentarily, it's not giving me any codes. Again, I've read that on the ABS port, while retrieving the codes, I should have driven the car above 35 mph. and check the codes without turning off the car. Is this correct? if not, then I'm clueless.

 

The ABS computer may be at fault, primarily the blade fuse. It's located under the dash on the driver's side, hard to see but it's up there! Get to it and replace the fuse before anything else.

 

sorry about under-the-seat thing, I dunno what I was thinking of, of course, thats the SRS under the seat, not the ABS.

the fuse lev talks about is on a surge protector relay thats next to the ABS module itself. this relay turns on with the ignition switch and provides power to the ABS module, it will shut off if there's an overvoltage spike (probably something north of 15 or 16V) to prevent damage to the ABS controller.

 

OK... Lev was right. The fuse was blown. I put a 15 instead of a 10 (because I lacked a 10) and finally, after 3 years since I had the car, the ABS is off. Knowing my luck, this might be a Pyrrhic Victory. Once I turned the engine and was ecstatic because the light turned off, I went to check to see if there were any codes in the OBD Case "A" Port 3, and no flashes at all. The Case "B" Port 2 still the light remains completely on the moment it touches the prong. So, I don't think that's the port. Any ideas why no readings?

 

As long as the light's off, you are good. Don't worry about the dodgy diagnostics! Light comes on, then off once the car's started, right?

 

Lev. yes. It lights on, then off. But no diagnostics. So, I'm good.

 

Good life rule: "Avoid the pursuit of perfection!" It's just a marketing ploy!
You'll live much longer and definitely happier!
Especially relevant when it comes to old cars.

 

Tell that to my OCD...