Intermittent communication failures between diagnostic tools and vehicle modules can be frustrating. This article outlines a real-world troubleshooting experience with a Mercedes-Benz W211 exhibiting symptoms indicative of a “Data Transfer Has Failed Das To Xentry” scenario, ultimately pinpointing the root cause and solution. We’ll explore the diagnostic process, highlighting the importance of the Central Gateway (ZGW) module in CAN bus communication.
Diagnosing Intermittent CAN Bus Communication Errors
A W211 presented with intermittent operational issues including warning lights, flashing dome light, erratic A/C behavior, and eventually, a complete no-start condition. Initial diagnostics using XENTRY revealed numerous stored faults across various modules, pointing to CAN bus communication failures on both powertrain and body networks. The logged faults indicated intermittent issues, suggesting a potential wiring or connection problem rather than a complete module failure.
Initial inspection focused on the CAN bus distributors and wiring harnesses. A minor chafe was discovered on a CAN wire near the aluminum foot plate under the right dash. This was repaired, but the problem persisted. Subsequent failures led to a re-examination of the diagnostic codes, which again showed similar CAN communication errors.
The Central Gateway (ZGW) as a Critical Point of Failure
Consultation with a seasoned Mercedes-Benz technician suggested checking for water intrusion in known problem areas: the rear SAM module in the trunk and the ZGW (Central Gateway) module under the dash. Water damage to the ZGW is often caused by clogged sunroof drains leaking into the wiring harness.
Inspection of the rear SAM revealed no signs of water damage. However, upon removing the ZGW, corrosion was evident on the connector pins, particularly those associated with the engine and body CAN buses (pins 7, 8, 9, and 10). Internal examination confirmed corrosion on the corresponding circuit board contacts.
Cleaning the ZGW and Restoring Communication
The corroded pins and circuit board contacts were meticulously cleaned using isopropyl alcohol and fine tools. After thorough cleaning and drying, the ZGW was reinstalled. The vehicle started immediately and successfully completed multiple start/stop cycles without further issues.
Conclusion: ZGW and “Data Transfer Has Failed DAS to XENTRY”
This case study demonstrates that “data transfer has failed DAS to XENTRY” errors in a W211 can be attributed to a corroded ZGW. The ZGW acts as a central communication hub for the vehicle’s various modules. Corrosion on its connectors disrupts CAN bus communication, leading to intermittent and seemingly unrelated failures. Thorough inspection and cleaning of the ZGW can resolve these issues, restoring reliable data transfer between DAS and XENTRY and ensuring proper vehicle operation. If you encounter similar communication failures in a W211, the ZGW should be a primary suspect in your diagnostic process.
