ABS malfunction

[aznpersuasion]

it started randomly, if i hit a bump the ABS light would trigger. if i turned the steering full left and brake the pedal would modulate and ABS light would trigger. now as soon as i brake after starting the truck the pedal will modulate and ABS light will trigger. after the ABS light triggers and pedal modulates it will continue you operate normally as if nothing was wrong (however i have never needed to panic brake yet). thoughts? sensor? fluid is full

 

[lesterl]

Clean the tone rings on the axle shafts, they can get rusty and cause false activations. If that doesnt fix it, then you may have a bad ABS module.... Cheap stuff first.

 

[aznpersuasion]

Makes sense since one of my shafts is slinging grease everywhere. Thanks.

 

[lesterl]

Grease probably wont affect the sensor, but metal filings and rust can fool the sensor, also a bad bearing will throw it a kilter...

 

[aznpersuasion]

Doing this right now. I didn't realize the ring wad in the bearing assembly and not on the shaft. Cleaned the pick up and ring as best I could. On to the driver side now. Only grease so far, no metal.

 

[samotahoe]

could be bad bearings, seen that before

 

[aznpersuasion]

just enough to send a bad signal? because they feel fine. what about the ABS computer? anyway to check that? or anyway to scan ABS code?

 

[lesterl]

Sounds like a defective module.... dont even know what year your rig is.... can pull codes out of ABS if you have a scantool....

 

[aznpersuasion]

I'll try to see if my obd2 scanner will pick anything up

 

[samotahoe]

I'll try to see if my obd2 scanner will pick anything up

unless you paid big bucks for your scanner it wont read the abs module. you might need to find a scanner that specifically checks the abs module and is able to reset anything thats there.

the bearings can have very little, but enough play that the speed sensors will not be able to see the signal to the axles while turning or on bumps which can trigger the light because of the dropout in signal

 

[lesterl]

my $200 innova scanner will read ABS.......

 

[samotahoe]

great! did you check for codes yet? any update?