The Audi A6, particularly the 1999 model (C5 or Typ 4B chassis), is known for its blend of luxury and performance. However, like all vehicles, it can experience technical issues. A diagnostic scan is crucial for pinpointing problems. This article breaks down a recent VCDS-Lite scan performed on a 1999 Audi A6, revealing key error codes and what they might indicate for owners and technicians working on this model.
The initial auto scan of this Audi 99 A6 revealed a single fault code within the automatic transmission system. Specifically, the scan reported:
- 00266 – Solenoid Valve 5 (N92): Short to Plus
This error code, related to solenoid valve N92, suggests a potential electrical issue within the transmission. A “Short to Plus” typically indicates that the solenoid circuit is experiencing an unintended connection to a positive voltage source, which can disrupt the valve’s proper operation. Solenoid valves are critical components in an automatic transmission, controlling the flow of hydraulic fluid that enables gear changes. A malfunction in valve N92 could lead to shifting problems or other transmission performance issues in the Audi 99 A6.
Further investigation was conducted by toggling through the transmission outputs using VCDS-Lite. This action, while exploratory, resulted in the appearance of additional error codes in the subsequent auto scan. These new codes were:
- 00526 – Brake Light Switch-F: Implausible Signal
- 00270 – Solenoid Valve 7 (N94): Short to Plus
The appearance of the brake light switch error (00526) after manipulating transmission outputs is interesting and might be related to electrical crosstalk or an issue triggered by the output tests. It’s important to note if this brake light switch error is consistently present or only appeared after the output test.
More significantly, a second solenoid valve error, 00270 – Solenoid Valve 7 (N94): Short to Plus, emerged. This reinforces the initial finding of a potential electrical problem within the Audi 99 A6’s transmission solenoid circuits. Having two solenoid valves reporting a “Short to Plus” condition warrants a thorough examination of the transmission wiring harness and potentially the transmission control module.
Interestingly, while the transmission system showed these faults, other modules in the Audi 99 A6, such as the engine control unit, ABS brakes, HVAC, airbags, instruments, central locking, seat memory, interior monitoring, and radio, reported “No fault code found” in both scans. However, the interior monitoring system (Address 45) did show multiple intermittent faults related to glass-break sensors from a previous scan, indicating a possible separate issue with the alarm system that might require attention.
In conclusion, the diagnostic scans of this Audi 99 A6 highlight potential electrical issues within the automatic transmission, specifically with solenoid valves N92 and N94. While the appearance of the brake light switch error needs further verification, the consistent solenoid valve errors suggest the next steps should involve a detailed continuity check of the transmission wiring harness. If the wiring checks out, further analysis of the transmission control module itself may be necessary to resolve these fault codes in this Audi 99 A6.
