The keyless entry system (Kessy) on my used 2016 Volkswagen Touareg has been malfunctioning since purchase. The remote works intermittently, requiring close proximity to the vehicle for locking/unlocking. Touching the handles for passive entry is also unreliable, functioning better when the key is not in my pocket. The passenger side seems slightly more responsive. Both keys exhibit the same behavior, and no fault codes are present.
The selling dealer agreed to cover repairs at my local VW dealership. They ordered a new key, claiming both original keys were faulty, a conclusion I disagree with. Unsurprisingly, the new key performs identically to the old ones. The dealership has been “running tests” for two days without resolution.
Reviewing the official wiring diagrams on Erwin, I’ve developed a potential diagnosis.
Understanding the Touareg’s Kessy System
My understanding of the system is as follows:
1. Door Handle Touch: When a handle is touched, the local door antenna signals the key fob to unlock. The LED on the key fob should flash, even if the door doesn’t unlock. The key fob then transmits a signal to the remote control antenna embedded in the rear passenger side window. Is this accurate?
2. Antenna Connectivity: A disconnected or damaged antenna within the glass or its wiring to the antenna module could significantly reduce the key fob’s operational range, particularly on the driver’s side. Is this a valid assumption?
3. Antenna Module Functionality: Since there are no fault codes, the antenna module located in the trunk, beneath the rear passenger side window, is likely functioning correctly. This would explain the lack of error messages despite the poor performance. Is this assessment reasonable?
Possible Diagnosis: Faulty Cabling
Based on these points, I suspect the issue stems from a faulty connection between the antenna module and the antenna embedded in the glass. The intermittent functionality and lack of fault codes point toward a connection problem rather than a complete component failure.
Conclusion: Next Steps
Could a faulty cable connection be the root cause of my Kessy problems? Further inspection of the wiring and connections between the antenna module and the glass antenna seems to be the next logical step in diagnosing this issue. Experienced Touareg technicians or those familiar with the Kessy system, please share your insights.
