A user was experiencing issues with their cruise control system and sought assistance in diagnosing the problem using VCDS, a diagnostic software for VAG (Volkswagen Audi Group) vehicles. Initial checks of Measuring Value Block (MVB) 006.2 for clutch, brake feedback, and controller #16 for switch information were suggested. The user confirmed these checks were performed and provided the following VCDS log data.
The log data reveals several key insights into the cruise control system’s behavior:
Analyzing the VCDS Log for Cruise Control Issues
The provided VCDS log shows data from Address 16 (Steering Wheel) and Address 01 (Engine). Let’s break down the information:
Address 16: Steering Wheel Module
- Group 004: Cruise-Cntrl-System: Initially, this group indicates that the Cruise Control System is “ON” but both the “Main Switch” and “CCS-Set” are “Not Oper.” This suggests a potential problem with the cruise control stalk or its connection to the steering wheel module.
- Subsequent Group 004 Readings: Later in the log, “Main Switch” changes to “Activated” and “CCS-Set” changes to “Resume”. This indicates the cruise control stalk buttons are functioning and communicating with the module. The change in status suggests the initial “Not Oper.” readings might have been due to user interaction or a temporary fault.
Address 01: Engine Module
- Group 006: Cruise Control System (CCS): This group provides data on vehicle speed, pedal monitoring, and switch monitoring. The “Vehicle Speed (actual)” being 0.0 km/h in both readings indicates the vehicle was stationary during the test.
- Cruise Control Pedal Monitoring: The binary data “00101100” and “00101000” in this field represent the status of the brake and clutch pedals. A change in these binary values would indicate pedal actuation, which could disengage the cruise control. The slight variation suggests a possible momentary interaction with one of the pedals.
- Accel. Pedal Pos. Sensor 1 (G79): A reading of 0.0% indicates the accelerator pedal was not pressed.
- Cruise Control Switch Monitoring: The binary data “10000001” remains constant, suggesting consistent signal reception from the cruise control stalk switches.
Conclusion and Next Steps
While the VCDS log provides valuable information, it doesn’t pinpoint the root cause of the cruise control issue. The intermittent “Not Oper.” status in Address 16 warrants further investigation. Possible causes include a faulty cruise control stalk, wiring harness issues, or a problem within the steering wheel module itself. Further diagnostic steps could include checking for fault codes in both the steering wheel and engine modules, visually inspecting the wiring harness and connections, and performing more dynamic tests with VCDS while driving the vehicle at various speeds. Addressing any found fault codes and checking the wiring harness are recommended next steps in diagnosing the cruise control problem.
