ABS/Traction Control lights on: 1996 Fleetwood

1996 Fleetwood Brougham, 105K miles. The ABS and Traction Control dash lights are generally on; sometimes off but only for a few hours. When I go to the diagnostic mode of the Climate Control System, advance to -04 for the ABS codes, the display toggles between 123 and 161, which I assume are DTC 23 (RF wheel speed sensor circuit continuity malfunction) and 61 (BPMV pump malfunction). Maxi-fuse number 5 for the ABS is good. The RF wheel speed sensor is shattered. I'm waiting on the replacement part. What should I be looking for to troubleshoot the BPMV pump circuit? Is there a way to test the pump independently of the control module (jump the wires directly to the pump?). Single wire leaving the pump is a ground, so power must be applied through one of the terminals of the control module.

My local GM dealer is a as useless as balls on a heifer in diagnosis of the system, won't even try, and claims that the car is too old to communicate with their laptop-based scanners. I'm plowing through the FSM on the systems. It calls for a Tech Scan1 and breakout box to for diagnosis. I'm told that Tech Scan 2 is back-compatible. I'm out of my depth in this area, but reading and re-reading the FSM to learn more.

Is there anyone in driving range of Geneva NY who might be able to have a go at this issue? I have a complete ABS/Traction control module and pump with bracket to swap out if necessary, but it is more common for these issues to be due to broken wires and dodgy connections, so a pump swap without prior confirmation of the wiring seems unlikely to advance matters.

The yellow connectors are notorious for disintegrating. There are four of them on a caddy. One on each wheelhouse, and one for each rear wheel. I reconnect the wires, with shrink wrap on each wire, then ziptie each pair in place.

Hi Fred,

The connector on the RF wheel speed sensor pigtail is white (or it is now), and seems OK. Terminals inside are bright. I need to check for continuity back to the control module in the rest of the wiring, but it looks OK and only the RF sensor is tripping a DTC. The RF sensor body was cracked at the steering knuckle, and the magnetic probe on the disk side was chipped.

I've been told that when you hear hoofbeats, think horses, not zebras. So, I'll follow your advice and chase down any possible breaks in wiring first, along with checking the ground for the ABS pump. It looks like it could use a cleaning. Hopefully, that clears the issue with ABS/Traction Control. The warning light on the Traction Control is likely due the the ABS problem, as any issue with ABS automatically disables the traction control and flips the Traction Control warning light to "on", and disables both systems.

Found that ground for the ABS pump was poor and cleaned it up. Hopefully that improved matters, but won't know until the wheel speed sensor arrives and gets installed. Is there a way to clear codes through the climate control system? I can read them, but haven't found the secret to clearing them yet. FSM says ABS DTCs will clear after 100 consecutive ignition cycles if the fault does not reoccur, but that seems like a great way to waste a day and kill an ignition switch, starter, and battery. Continuity of the wires back to the control module from the RF sensor connector is good according to my multimeter, which bodes well for solving that issue with a new sensor.

On Facebook, a guy from Estonia piled onto a thread on this problem and suggested removal and cleaning of the ABS motor internals, which the FSM says is not serviceable, but which he has sucessfully done twice on two different Fleetwoods. He must have the only two Fleetwoods in the Baltic States. Removing two screws will free the motor from the BPMV, and you can pry back the ears on the motor housing end caps to take the motor apart. If the motor seems frozen, and if all else fails, I may have a go at that, but only as a last resort.

Fred: you were right about the color of the wheel speed sensor connector. Upon further cleaning and better lighting, it is yellow. But so far it has not broken and is weathertight.

Does the brake computer forget if you remove power?

It does not.

Woo hoo!  It's fixed!  I first cleaned up all the grounds.  That made me feel better, but the problem persisted.  Then I replaced the RF wheel speed sensor.  It was in several pieces, but maddeningly replacing it did not help: same codes as before.  I finally found a mechanic with a proper scanner, knowledge of how these cars work, and who was old enough to have been eating solid food in 1996.  The problem was a packed up ABS pump and a bad control module.  Fortunately, I had a complete donor unit (Nick: your Fleeetwood did not die in vain).  Swapped it out, went through the "auto-bleed" procedure, and POOF.... it's fixed.  All warning lights are out.  Traction control works.   ABS works (tested on ice).   Life is good.  The car is in hibernation until Spring, and then ready for a real road trip.

She really looks like a mean little girl. I bet she tortured her pets when they did not listen.