'95 4WAL code 38

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majack82

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I am working on getting the ABS functional on my 1995 K1500 since it's not worked the entire time I've owned it. It had a wheel speed sensor code for the front left, so I replaced the wiring harness and reset codes. The light went out so I was happy that took care of it. Took off on a test drive and a short time later the light came back on with a code 38 set, which is "Wheel Speed Error". The manual says the BPMV is seeing "the signal from one sensor at more than double or less than half the frequency of the other sensors for a 12 second duration". My speedometer has read fast since I've had the truck but as time has progressed it's gotten worse. Started off about ~2 MPH off at 55 to now between 4-5 MPH off. The driveline and tire size on this truck is 100% bone stock and has never been altered in any way, so I don't really know why the speedo would be off but I am thinking that's the cause of the code I'm getting from the ABS system now. Has anyone else experienced your speedo being off for no good reason on a stock truck? Did you replace the DRAC to fix it? What's really strange is the odometers read distance correctly. It's just the speedo that's wrong.

It goes without saying but probably needs to be said anyway - if I wanted to remove the ABS, I would not be asking how to fix it. Please don't suggest removal as a "fix". That is not helpful. Thank you.
 
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Schurkey

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Perhaps a moderator will move this thread out of ENGINES and into Axles + Brakes.

5 mph error at 55 mph from the trans/transfer case isn't "more than double, or less than half" of the other speed sensors.

Connect a scan tool. What do each of the speed sensors show for vehicle speed?
 

majack82

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I didn’t realize there was a sub-forum for brakes. Apologies for posting to the wrong place.

I don’t have a scan tool that can measure the speed sensors, which is why I was asking for help here. I thought perhaps someone else had run into this already and had some advice.
 

majack82

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I reset the codes in the ABS module again, and so far I haven't had any more issues. I guess the 38 was a fluke, but either way, it's fixed now and all is well.
 
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