Why does the abs light & traction light come on at the same time my brake pedal gets hard & then goes back to normal?

You obviously still have ABS System problems &,
should have codes, to use to diagnose the issue
as was the case with the first hub assy R&R

You most likely are NOT getting the correct wheel speed
sensor data for some reason,find out why !

That is why the abs module is pulsing the brakes

All your doing is applying the brake pedal

That is the only computer input,so maybe the
switch is loose or bad- next to the brake pedal

I would scan for computer data & codes- especially
the body & abs braking system

It is safe to drive. You need a scan tool to get a code out of it. Could be as simple as a wheel speed sensor going bad. All of these lights will work together normally. The traction control uses the ABS to gain traction, and the Brake Assist System is part of the stability control. Also uses the ABS.

sometimes something like this can be bad tires or bad brakes. first inspect your tires and brakes. it also depends on how fast you are going it could be normal actually. now my fathers s10 did the same thing but his brakes started clicking and slower to stop, but his abs computer was bad.

THIS IS A WHEEL BEARING ISSUE

abs=anti-lock brake system/ tcs=traction control system ==sounds like you have a problem with ur abs possible bad sensor or a wiring connection problem when abs shuts down [trouble light] your brakes will work normal but if u stomp or brake hard the brakes will lock up skid and the tcs doesnt affect brakes but if u accelerate hard tires will spin lose traction check the wiring and connections to the sensors sometimes debris hits the wire and loosens the connection if looks ok and light is on have car scanned for the trouble code most auto stores such as auto zone/advanced auto offer this service for free the code will what and where the problem is so repair can be made

If brake pedal is chattering or pulsating it is most likely because you need either front or rear rotors, or both. They are rusted or out of round. If there is something wrong with either your abs or traction control,the abs or traction control light will come on & stay on. As soon as these lights come on, it automatically disables abs or traction control. If you would like to take out fuse that disables abs or traction control circuits, it will leave the lights on.You just wont have their functions. If by some strange condition your chattering goes away, then there is indeed something wrong with your abs or traction control.Fuses are labeled abs or traction either under hood or in your fuse panel in car.

If your ABS light is on then you will have to get the codes read to see what sensor is giving you the problem.The ABS light being on will also affect the traction control and brake pedal going to floor.Auto Zone will check codes but I`m not sure if they do ABS codes.They don`t charge so it wouldn`t hurt to ask.After you get the codes you can post back and I can help you find the problem.Good luck.

it might be a loose abs cable behind one of the brakes?

I can't answer the question about the gas fumes, but I had the same problem last year with the "Service Traction Sysytem" message and the Trac and ABS lights coming on in my Impala. Mine turned out to be because of a bad wheel bearing, that was causing the ABS and traction system not to work. I'm not sure if you've experienced this, but another thing that would happen with mine was that I would go to brake and have a hard time depressing the brake pedal, almost like it was pushing back. That is the point when the Trac and ABS lights came on.