I have a 94-95 ABS unit on my AI Mustang ('89). It worked flawlessly in March of this year at the first race of the year. However, after a 6 month rest, the diagnostic light would not go off during normal driving, but would at the track during hard braking, as witnessed on my in-car video. Now, the ABS doesn't work at all and the diagnostic light won't go off at all regardless of braking effort.
I'm currently getting a code "34" (Left Rear ABS sensor continuity fault). Although, I have probed both wires for continuity all the way back to the ABS pump and all is fine. I've even replaced that sensor with another, just to make sure the sensor is okay. No change.
Here is where it gets wierd... I have a spare pump assembly that was going to replace this misbehaving unit. When I pluged it in, the code "34" went away, but is now replaced by a code "43" (left front ABS sensor) and code "63" (voltage supply interruption). If I switch back to the old unit, I get only the code "34" again.
So, to summarize
Pump #1 (Currently in the car)
1. Worked great 8 months ago
2. Worked "marginally" a month ago
3. Does not work now and throws code "34" (Lft Rear Continuity Fault)
Pump #2 (Spare)
1. No code "34"... this is a start.
2. Shows a code "43" (Lft Front ABS sensor)
3. Shows a code "63" (Voltage Supply interruption) probably due to it not being plugged in for very long.
4. When I plug in a new front left sensor, the code "43" is still there.
My big question is why do the pumps see different codes?
I'm tempted to get a 3rd pump off E-bay just to confirm, but wanted to take the car to the track this following Thursday and wanted the ABS functional...
AI #67 "Mosty Brothers' Racing" Mustang