posi trac & ETS

[tranceokido]

i had a question about the grand am's traction system. Pontiac eqquips the grand am gt with a posi track system right. And its LSD that has the job to differantiate the power between each wheelsso you don't just have one wheel spin and the other do nothing correct? Now the for the traction control system, how does it work? I know it reduces power but how does it reduce power? Does it also use the brakes at all?

[Mike Jung]

The GA has no LSD.

The traction control system senses different wheel speeds via the ABS system. It reduces the front drive wheel speeds by up-shifting the tranny or/also reduces the engine speed...no brakes are used.
It does not do skid control corrections.

[Weem]

Just to add to what Mike said, I believe that the ETS reduces engine speed by retarding the timing, which is why it can be a little stinky if you make the ETS stay on for a long time (i.e. flooring it while driving on thick snow pack).