OBD1 ABS codes

[scott2093]

Getting around to addressing my brake situation. !st time getting into them.

Fronts look good. Greased sliders and pins.

Redid rears...new drums, shoes, hardware and wheel cylinders....would rather do many many many other things than rear brakes..wtf...

Still need to figure out my parking brake issues. Pedal to activate it doesn't seem to be working right...Clicks but I can pull it up by hand and my release handle wants to pull out of it's housing too easy....

Never used the ABS section of my scanner....


I put in 4WAL,light duty truck, non-linear egr.... and have a bunch of codes
36-Missing vehicle speed sensor signal
37-Erratic vehicle speed sensor
41-open isolation selenoid right front
42-open pulse width modulation selenoid right front
45-open isolation selenoid left front
46-open pulse width modulation selenoid left front

cleared them with scanner but they are not cleared when I read for them again...
There's a method in manual to jump a and h terminals on the aldl port but that's for when brake light is staying on....

No brake light on....
Brake light comes on koeo for a couple of seconds then goes away..
brakes work great....all this chasing around nice pedal feel was cured with actually having working rear brakes? ...... Haven't done any slamming of brakes yet...
Not being able to clear codes points to replacing bpmv in manual....

 

[Schurkey]

WHAT VEHICLE???

 

[scott2093]

1993 GMC Yukon

 

[Schurkey]

EBC4 ABS?

What scan tool?

 

[scott2093]

EBC4 ABS

I'm not sure if you're asking me,telling me or taking a guess? I don't know. I'm guessing it's 4wal is as far as I've gotten. Looking quick online, I would guess yes..EBC4?

What scan tool?

SPX/Mac Tools Taskmaster ET3008A

Also, when the manual mentions brake light, am I supposed to be seeing "ABS"? All I see is "brake" for a couple of seconds when koeo.....and when I push parking brake.... no ABS light...

 

[Schurkey]

I'm not sure if you're asking me,telling me or taking a guess?

Educated guess. I'm fairly sure it's an EBC4. I've never worked with that system.

Instructions attached.

SPX/Mac Tools Taskmaster ET3008A

I've only worked with Snap-On scan tools, not OTC/SPX.

Also, when the manual mentions brake light, am I supposed to be seeing "ABS"? All I see is "brake" for a couple of seconds when koeo.....and when I push parking brake.... no ABS light...

If the manual is calling-out the BRAKE light, they mean the BRAKE light, not the ABS light.

But I'm surprised that the ABS light isn't lit-up. Makes me concerned that there's a fault in that circuit somewhere, including a failed bulb.

 

[scott2093]

But I'm surprised that the ABS light isn't lit-up. Makes me concerned that there's a fault in that circuit somewhere, including a failed bulb.

Yeah, looks that way.
I'll investigate......

 

[scott2093]

ABS bulb was blown. Swapped the one from "belt" and ABS lights up koeo...Goes away after a couple of seconds.
ABS light Comes back on when truck is started...Then goes right away....
Same codes....

36-Missing vehicle speed sensor signal
37-Erratic vehicle speed sensor
41-open isolation selenoid right front
42-open pulse width modulation selenoid right front
45-open isolation selenoid left front
46-open pulse width modulation selenoid left front


Datastream limited--
at idle

--ABS warning-off
--brake switch status- off...unless I push brake
--brake warning lamp-off
--Lf speed - 5km/h
--Rf speed -5km/hr
--Rear wheel speed--5km/hr

Guess I'll watch when I drive....not sure what's up with that.....

 

[scott2093]

ok...
driving reflects the speed info...weird that the rear speed seems 2 or 3km/h faster but reflects on dash accurately.......

abs light came on and stayed on entire 10 minute drive

scanner showed abs warning light on.....

 

[Schurkey]

Ideally, you'd be able to clear the codes and see what comes back.

If the speed sensors are all showing the same value, I'd expect your "36" and perhaps your "37" to go away. That leaves only fault codes for the ABS unit itself. If the rear speed is slightly different from the front...are the tires inflated properly? Tire size difference?

At least the ABS light can annoy you now