2000 323ci tractn ctrl lt comes on and stops power to rear wheels

depending if its front or rear if its in the rear most likely the brake wheel cylinder , and your brakes is part of the traction control why its off, you should make sure brake fluid is full and get it fix

wheel speed sensor, front right I believe.

I have had this on B.M.W`s the traction control sensors on the front or rear hubs pack up,the quick way to check this is diagnostics it works cheaper in the long run..Good-luck....

is this the front brakes doing this?? or the rear?? i would recomend changing pads and rotors and drums(rear) and shoes(rear)

sounds like maybe a wheel speed sensor or a broken wire to the speed sensor.

If the ABS (and likely the traction control) light came on at the same time that the speedometer stopped working, you likely have a faulty wheel speed sensor at the right rear wheel. You can test this by swapping the two rear wheel speed sensors (ABS sensors). If the speedometer then works (but the ABS & Traction control lights stay on), replace the sensor that is now at the left rear (was at the right rear). If no change, you may have a fault in the ABS & Traction control - control unit.

Rear wheel speed sensor at www.bavauto.com

http://www.bavauto.com/shop.asp?HC1=0&Htarget=search.asp&HCY=2001&HCM=330i&SearchStr=rear%20abs%20sensor

This is not going to sound possible but it happened in my 1994 Crown Vic too. If you have traction control part of the system controls an air valve in the air filter intake area. When the traction control senses a difference in rear wheel speed it chokes the engine so you don't spin the wheels.
Your sensors must be dirty or the emergency brake pads are covering the sensors with brake dust. You need to have someone check the rear brakes.

You motor will produce that hum as air is choked off by the traction control.

the major difference in the tire size is enough to cause the traction control to activate the car sees a speed difference between the front and rear tires and thinks it is slipping it will continue until you replace the other two tires

We were having this problem...have your wheel bearing checked out. There was a sensor in the drivers side wheel bearing...once we replaced it (because it was going out) the ABS and Traction Control warning lights stopped coming on.

that is what it is desgined to do - reduce acceleration and apply the brakes intermittently when the wheels spin. You have a switch you cn push to disable it. You need to disable each time you start car. See owner manual.

06-10: Traction Control 1996 Contour, Mystique Workshop Manual
DESCRIPTION AND OPERATION Traction Control System The optional traction control system is designed to control wheel spin when accelerating on slippery or loose surfaces. Traction control system is available only with anti-lock brakes. The traction control system includes the following components:

• Hydraulic control unit.
• Throttle control actuator (9N825).
• Traction control switch.
• Traction control warning indicator.
• Front brake anti-lock sensor (2C204).
• Rear brake anti-lock sensor (2C190).

The traction control system operates as follows:

• System functions by transferring torque from the spinning wheel to the wheel with the most traction.
• This is achieved by applying the brake at the spinning wheel through the hydraulic control unit or reducing the throttle opening.
• Traction control braking and throttle control occur at vehicle speeds up to 50 km/h (30 mph).
• At vehicle speeds above 50 km/h (30 mph), only throttle limiting control is used.
• If speed control is operating when traction control system engages the traction control system will disengage speed control through the use of a speed control relay. This action is the same as applying the brake pedal with speed control engaged.

1996 contour
Traction Control Switch The traction control switch is located on the instrument panel, left of the steering column.