Keyless Systems - Intermittent Hands Free Trunk Concerns
55 Hands free trunk release intermittently inoperative55 13 29
2031273/3
March 29, 2013
Supersedes Technical Service Bulletin Group 55 number 13-28 dated February 27, 2013 for reasons listed below.
Vehicle Information
Condition
The movement-activated rear lid opening (also known as Hands-free trunk release") sporadically is inoperative.
This feature is installed on all A8 vehicles with Audi advanced key (PR No. 413) from CW 45/2011 production.
Technical Background
Hands-free trunk release system, operating parameters
1. The system is only active when the ignition is switched off.
2. The function works via the advanced key system. Operation may temporarily be affected from other signal transmitters. Examples include additional remote keys or a cell phone in the same pocket as the vehicle key or interference from nearby transmitters of the same frequency (TV transmitters, wireless headphones, other vehicle remote controls, etc.).
3. The optimal movement is a straight forward and backward motion of the foot under the rear bumper (Figure 1). Other movements, such as from left to right or holding the foot under the bumper, may not be recognized by the system.
4. The optimal foot position as at an angle of 900 between foot and leg (Figure 1). If the foot is stretched out, the detection range of the lower sensor cable may not be reached.
5. The optimal area for detecting foot movement is shown in the illustration; areas to the left and right may not recognize the movement (Figure 2).
6. When performing the foot movement you should stand at least eight inches behind the vehicle. If you are closer than eight inches to the vehicle, your foot movement may not be recognized.
7. The system can detect moving water underneath the vehicle. If moving water is detected, the hands-free trunk release is deactivated for safety reasons for about a minute. This also prevents opening the trunk unnecessarily (for example, in a car wash or during heavy rain). The moving water detection may also be activated with movements other than those described in point 3.
8. Dirt and salt on the rear bumper and rear underbody of the vehicle where the sensor cables are installed can affect the electric field which recognizes the foot movement. This area must be clean for proper system operation.
9. Immediately after closing the trunk lid, the hands-free trunk release is disabled for a few seconds.
Production Solution
Not applicable.
Service
Explain the system behavior and concept related-restrictions to the customer.
Warranty
This TSB is informational only and not applicable to any Audi warranty.
Additional Information
More information on this system can be found in the following resources:
^ Owners Manual insert: Owner's Manual Model Year 2013 Audi A8 Movement-activated rear lid opening (Part #: MY13A8OMINSUS)
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.