The Audi A4 steering racks can have a port in the rack body for a vehicle’s speed sensor. If the wrong steering rack is fitted for the vehicle’s speed sensor then problems can occur.
What the Speed Sensor Port Does
Note that the speed sensor connects to the steering rack via the mentioned port and sends road speed to the power steering control unit. This then enables speed-sensitive steering, or in other words, increases the amount of steering assistance needed at higher road speeds and reduces it at lower road speeds.
Which A4 Variants Use It
For most B6 and B7 Audi A4 models (produced from 2001 until 2008) which are equipped with a steering rack, that rack will have a port for a speed sensor on the body of the rack near the pinion end. The higher spec models equipped with speed sensitive power steering will have a ported rack, whilst the lower spec models (equipped with standard hydraulic steering) will not have a port in the rack.
Checking Your Existing Rack
Check your current steering rack for a small threaded boss on the rack body near the pinion end. Some are blanked off, but if your current rack has a port in it, then the replacement must have a port in it as well. This is a requirement under vehicle type approval for replacement components.
There is more on Audi A4 steering rack at https://westernpowersteering.co.uk/vehicles/audi/audi-a4-b7-steering-rack-without-speed-sensor-port/.
Symptoms of the Wrong Spec
The consequences of the wrong spec Steering Rack are now clear to you, as without a connection point for the speed sensor, the sensor has no connection point, and this results in very heavy, hard and unchanging, (i.e. without variation) steering at all times, and a warning light on the dashboard.
Matching the Correct Spec When Sourcing
We list all the steering racks for the A4 B7 by specification. Check your VIN and the specification of the current steering rack to find the correct speed sensor port on your new rack.
Getting the spec right first time saves a costly return and repeat labour.
