Wheel speed sensor question

[Scoobey1]

I'd be grateful for a little advice on a mechanical issue for my 2000 Z71: the wheel speed sensor(s?) are malfunctioning, activating the "ABS" light and making braking funky: at slow speeds, the truck (believing the wheel was skidding) would release the brake and the car would keep rolling even with the brake pedal depressed. I pulled the ABS relay from the fusebox, and the brakes work fine (but without ABS working, of course).

I've read elsewhere that the sensors just need to be removed and cleaned, but my (usually good!) mechanic says on this truck the sensor is integrated into the hub, and can't be r/r'ed separately. (Note that the '00 Z71 is mostly the same as the '99 Tahoe, NOT like the later, redesigned '00 Tahoes.)

Is he right? Also, how can I tell WHICH sensor or hub needs to be repaired/replaced? Thanks!

 

[Scottydoggs]

best to scan it for abs codes. need a abs scanner. most cheap scanners wont pull abs codes. my be your mechanic would be so kind to scan it and give ya the codes. most shops around me will charge you for a abs scan.

or you can dl this free app. buy a 20 dollar bluetooth obd2 reader i suggest the bafx brand, the elm 327 has earned a bad rep over the last few years for not working. and then lastly, you need a droid device. phone or tablet will work.

when you scan it, find history, clear history. drive the truck, what ever code pops up first is likely the main issue.

ChevroSys Scan Lite - Apps on Google Play

Fast Read & Clear Trouble Codes: Chevrolets Vehicle (Engine, ABS, SRS, TCM)

play.google.com

this one is 14 bucks. https://www.amazon.com/BAFX-Products-Wireless-Bluetooth-Diagnostic/dp/B005NLQAHS

 

[OR VietVet]

2000*******https://www.rockauto.com/en/moreinf...OJnqpCLVrzuA+V+uWYyVz06cQ4SBmh4w/u7Tq7JgOiXCG

1999******https://www.rockauto.com/en/moreinf...OJnqpCLVrzuA+V+uWYyVz06cQ4SBmh4w/u7Tq7JgOiXCG

 

[Doubeleive]

I'd be grateful for a little advice on a mechanical issue for my 2000 Z71: the wheel speed sensor(s?) are malfunctioning, activating the "ABS" light and making braking funky: at slow speeds, the truck (believing the wheel was skidding) would release the brake and the car would keep rolling even with the brake pedal depressed. I pulled the ABS relay from the fusebox, and the brakes work fine (but without ABS working, of course).

I've read elsewhere that the sensors just need to be removed and cleaned, but my (usually good!) mechanic says on this truck the sensor is integrated into the hub, and can't be r/r'ed separately. (Note that the '00 Z71 is mostly the same as the '99 Tahoe, NOT like the later, redesigned '00 Tahoes.)

Is he right? Also, how can I tell WHICH sensor or hub needs to be repaired/replaced? Thanks!

abs sensors can be changed they run about $20-25 at the autoparts store, your mechanic is wrong
depending on your mileage and when the hubs were changed last it could be a worn hub or bad abs sensor, usually when they cause a problem braking it's just the sensor.
without having to spend money on a abs capable scanner you can simply buy one abs sensor and put it on one side left or right (sensor is the same either side) if the problem goes away great, if not then swap it to the other side. then if the problem still persist's it could be a bad hub.

 

[rockola1971]

Super common problem when the hub is on its way out because of excessive play. Easiest way to check is jack each front wheel up off the ground just enough to be able to spin it freely. Turn wheel by grabbing outer edge at 9 and 3 oclock and feel for roughness as the tire turns. Also grab tire at 12 and 6 oclock and try to rock inward and outward. If there is excessive play in the hub bearing you will feel it by doing that and it will be obvious.

 

[MassHoe04]

Sometimes ABS problems are not always the worst-case scenario...

I had an issue at highway speed only, where the ABS light would flash on and off and chimes driving me absolutely batty on my weekend commute! I thought the worst and feared bad hubs or having to replace all ABS sensors or the dreaded ABS module failure.

Turned out to be one bad ABS speed sensor on the front left.

I have a Tech 2 now, but I was able to identify a specific sensor issue with my Zurich scan tool from Harbor Freight. I got the "middle of the road" version that included reading ABS for about $100.

There were no general DTC codes on the top-level basic scan. But with a little digging, I managed to find a sub-menu called "GM OEM Enhanced". In there, I was able to see a specific code that not show as a DTC code on the main menu, but there it was in the GM Enhanced sub-menu. It pointed right to "Left Front ABS Speed Sensor".

I replaced that on sensor with a NAPA Ultra Premium ABS sensor. That did it! $28 and maybe an hour total. No problems since!

The Zurich pointed me to the exact part giving me troubles and saved me from the "try the part on one side and move it to the other side, if it didn't fix your problem on the first side" situation. Time may be less of an issue with hobby projects, but when you are dealing with a daily driver... Time is not always available.

Note: Just don't shove a new sensor in the hole and bolt it down! You want to be sure the tip of the sensor is not grinding on the ridges of the tone wheel inside the hub. That would grind the tip of the sensor off and probably make it fail.

Before bolting it down, press on the top of the sensor with your finger and rotate the hub. If you feel vibration coming up through the sensor to your finger or hear any kind of noise, it is rubbing the groves on the tone ring in the hub. You may need the shim.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.