Vehicle Application: 2003 BMW Z4 2.5L and 3.0L, and 2004 Z4 2.5L
Customer Concern: The electric power steering is not working properly.
Potential Causes: Defective electric motor power steering (emps), blown fuse or damaged wiring harness.
1. The electric power steering system on this vehicle is a one-piece unit that has the control module and the power steering assist motor.
2. Check for proper power and grounds at the module. Fuse 22 and fuse 64 both feed the assembly. They provide battery voltage on the red wire and the green/white wire.
3. The brown wire should be chassis ground.
4. Other wires are for communication and a signal from the steering angle sensor. These values can be checked in the datastream of a scan tool, but should not be a problem if there are no related codes stored for them.
Tech Tips: The power steering assembly should always have a centering clip installed on the shaft whenever it’s removed from the vehicle. Once installed, the clip can be removed. A new module should have the clip installed; if not, return the module and get another one. Never install a used one because they will not be centered and clipped properly. New modules also require coding and steering angle initialization after installation.
Courtesy of Identifix.