1.5 hours until I'm due at a wedding, driving down the freeway, and the 4Runner freaks out. All the braking system lights come on, and an audible alarm starts. I pulled off as quickly and safely as I could, and turn off the truck. Wait a few, then turn it back on, and the lights and siren resume almost immediately. I still had plenty of brake pedal, the brake fluid was full, so I decide to do the remaining 2 miles home. Sure enough, just as I get to my driveway, the brake pedal becomes really hard, but I'm still able to stop with a lot of effort. I did some reading, and found the routine for pulling the brake system DTCs, which result in a 41, 51, 52, and 56. The VSC code appears to be 43.

If I've found the right code list, 41 is the front left speed sensor, 51 is motor lock, and 52 is motor stuck off. I can't find what code 56 would reference.
I used my OBDII reader, and there are no engine codes being thrown (I didn't expect any, since the MIL light is off. I've read some threads about gas cap, but that doesn't seem consistent with the issues I'm seeing, and it's been more than a week since I put gas in, so I would think I would have seen any problem earlier.

2004 Toyota 4Runner Limited, 4.7 liter, 4x4. Would love to get a more complete list of DTC descriptions, and any additional troubleshooting ideas that you guys can come up with.

After some reading, I was left with a couple of options.

1. Wheel Speed Sensor
2. Wiring
3. Control Module
4. Pump/Accumulator Assembly

I found comments by someone that tapping on the pump motor had made their dash lights and having done the same thing with starter motors in the past, gave it a shot. Sure enough, the alarm and lights went out. I'm not comfortable with driving it that way, so I need a new assembly. I am not made of gold, however, and $1800+ seems like highway robbery to me. Does anyone have a place to get better prices?

MOST LIKELy ur pump/abs system, its toast.
does the abs pump kick in with the ignition on?

At this point, it has ceased to kick on. I've initiated the search for parts, but they are stupid spendy.

what year is your car?...paid 250 quid for mine, bought off a forum member, search on ebay a used unit is usually between 250 n 450 bucks.
learnt 03 is slightly more expensive......search on ebay

It's an 04. Prices I am finding are over $1000 used, with the exception of one unit on ebay for $895.