Offroad Trailblazers and Envoys

Service brakes with bigger tires

Something not working right?

by Mirror » Sun Apr 16, 2017 10:24 am

I just installed 33" duratracs, when i drive for 30 mins my abs and brake notification light, service brake system warning all comes on, along with about 15 chimes. It never did this with my 30" duratracs. Has anyone else had this problem on an 02-05 model and fixed it? Apparently i cant reprogram the ecu to the new tire size.
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Mirror
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by larryk » Sun Apr 16, 2017 7:08 pm

Are the front and rear diameters spot on? Try checking the front vs rear using a tech2. Other that changing gear ratios....you should be ok. Tire size well just screw up your Speedo and performance
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by Mirror » Sun Apr 16, 2017 7:28 pm

Whats a tech 2?
Also exact same rims and rubber. Gears are still factory 3.73.
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by larryk » Tue Apr 18, 2017 7:03 pm

Hmmm... Tech2 is the GM scan tool. Kind of a super scan tool....

If there is more than, if I recall, a 2% valence between front wheel speed (as measured by the front wheel ABS sensors), and either the rear axle speed sensors (2006+) or transfer case speed sensors (2005-). If your truck is stock, and the front/rear tire sizes are the same, and same level of wear, it's probably a bad sensor....you really need a tech2 to easily ID which one...
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by bartonmd » Wed Apr 19, 2017 9:17 am

Yep, bad wheel speed sensor, very likely. More likely, a bad hub/bearing that's causing a wheel speed sensor to not read.

Mike
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