Nissan Repair: consult, hall effect sensors, 2005 nissan pathfinder

Question
I'm from bolivia
Dear Mr. Sudderth:
I have a 2005 Nissan Pathfinder SUV 4x4
Why turn on together the VDC and SLIP lights
and turn off the brake light, we have changed the rear speed sensor and the fault persists.
What we should review now?
Thank you in advanced

Marco Perez Luna
Bolivia

Answer
Marco,

The Vehicle Dynamic Control and the SLIP (Traction Control) are on the same circuit.  Basically, you have wheel speed sensors at each of four locations.  These are hall effect sensors.  That is, they generate a square wave with the tone ring and the sensor picks this up.  That way, the computer will know if a wheel is locked or slipping.  If you do not have a specific error code for one of these then the problem usually lies with the ABS unit since it is what controls the application of the brakes.  I would first flush the brake fluid with a good quality DOT3 brake fluid.  This means all the wheels come off and you get someone in the cab and bleed each wheel until the fluid comes out clean.  If the brake pads are work over half way down replace those pads.  Now, with fresh fluid and less compression from excess fluid behind the caliper pistons the ABS unit should be able to control the wheels.  Now, did you scan the vehicle?  If the check engine light is on there may be something more specific.  Email me back if you need mroe information.  But, if all else is well a good flushing of the brakes usually works to correct the problem.  Remember that brake fluid should be purged, bled, every two years.  This is especially true in a humid climate like Bolivia.  In the South Eastern, United States this is especially true as brake fluid attracts water from the air and the water is absorbed by brake fluid and it ends up rusting brake components.  If you need to purchase parts checkout rockauto.com or courtesynissan.com