95 Regal ABS light on

[Regal900]

Hello, hope you are doing well, I just bought a 1995 Buick Regal Custom with the 3.1L V6.

My ABS light is on and the seller told me that its a faulty wheel speed sensor. Also sometimes when I drive the speedometer is all over the place and the transmission gets confused. Sometimes it shifts late and sometimes the car barely accelerates from a standstill no matter how much gas I give it.

Yes its got enough ATF and its a very healthy red.

Is it really a faulty wheel speed sensor? Are the wheel speed sensors on the wheel bearings on all 4 corners like modern cars or is it like inside the transmission?

Thank you!

 

Wiring 2004+ Grand Prix Seats into a 1997-2003 Grand Prix

[Robert]

Welcome to the forums. I think you may actually have two separate issues here.

The ABS light certainly could be a wheel speed sensor, but the speedometer going crazy along with the transmission shifting late, getting confused, or barely wanting to move from a stop makes me suspicious of the Vehicle Speed Sensor on the transmission, not the ABS sensor at the wheel.

These cars have a VSS on the transaxle that the PCM uses for vehicle speed and shift strategy. If that signal is dropping out or jumping around, the speedometer can go nuts and the 4T60-E can start doing some really strange things. I would check the VSS connector and wiring first and, if possible, watch the vehicle-speed data on a scanner while driving. If the scanner speed is jumping around with the speedometer, you are definitely headed in the right direction.

The ABS system has its own wheel-speed sensors, so the ABS light may still be another problem altogether. I would scan the ABS module before buying any parts and see exactly which wheel/circuit it is complaining about. You can also check the sensor wiring and resistance, but a scanner showing all of the wheel speeds live makes this a lot easier.

One other thing to keep in mind is that 1995 is an oddball year on these W-bodies. It is basically the GM OBD 1.5 transition setup, so a regular cheap OBD2 scanner usually isn't enough. You need something that can actually communicate with the 94-95 GM system and preferably read the ABS module too.

As far as the transmission goes, I wouldn't condemn it yet. Make sure the ATF level is checked correctly, hot and running, and look over the VSS and wiring before doing anything major. If the fluid/filter service history is unknown, dropping the pan and changing the filter isn't a bad idea, but I would diagnose the speed signal first because the jumping speedometer is a pretty big clue.

And yes, the 95 Regal is kind of a one-year electronic oddball compared with the cars before and after it, but there is still plenty you can diagnose and repair on it.

 

[Regal900]

Thank you very much

 

[90blkgt]

One other thing to keep in mind is that 1995 is an oddball year on these W-bodies. It is basically the GM OBD 1.5 transition setup, so a regular cheap OBD2 scanner usually isn't enough. You need something that can actually communicate with the 94-95 GM system and preferably read the ABS module too.

Do you have any recommendations on a scanner? I have a 1995 Cutlass, so have the same need as Regal900.

I also have the same issue with an ABS light on, too. The local shop scanned it, and said the fault is with the right front wheel. They suggested checking the speed sensor wiring at that wheel, and if OK, to replace the speed sensor.

 

[Robert]

Do you have any recommendations on a scanner? I have a 1995 Cutlass, so have the same need as Regal900.

I also have the same issue with an ABS light on, too. The local shop scanned it, and said the fault is with the right front wheel. They suggested checking the speed sensor wiring at that wheel, and if OK, to replace the speed sensor.

Yeah, 95 is a total pain since it's that weird OBD 1.5 transition setup. A normal $20 scanner won't even connect.

If you don't want to go that route, look for an old Snap-on MT2500 "red brick" on eBay (just make sure it has the 95+ cartridges and the right 16-pin adapter) or an Actron CP9690 or Bosch OBD1300 kit. The Actron/Bosch ones are easier to find new, but ABS support can be hit or miss on the 95s. You could also do an ALDL to USB cable from 1320 Electronics and run TunerPro on a laptop if you don't mind messing with software.

As for the ABS light, the shop is right on the money. The wiring harness to those front sensors flexes constantly and the copper breaks inside the insulation, even if it looks perfectly fine on the outside. Put a multimeter on the pins and wiggle the wires around to check for continuity drops.

Also, check for rust buildup pushing the sensor away from the tone ring on the hub. If the wiring is solid, swapping the sensor (or the whole hub if the bearing is making noise anyway) is the move.

 

[90blkgt]

Thanks for the scanner and abs troubleshooting advice.