1999 Audi A6 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 1999 Audi A6 and How to Fix Them

Find Repair Location
Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
0%
25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 1999 Audi A6 cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty or malfunctioning sensor can lead to incorrect readings, causing issues with engine performance or other systems relying on accurate data.
  • Control Module: A faulty control module can lead to erratic vehicle behavior or failure of various electronic systems due to improper signal processing.
  • Throttle: A faulty throttle body or a defective accelerator pedal position sensor may be causing inconsistent throttle response.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 1999 Audi A6 cruise control isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When the vehicle speed sensor fails or the wiring harness prevents signal transmission, the speedometer is the first thing that will stop functioning properly. This can be an intermittent issue where the speedometer only works occasionally, the speedometer may cease all function, or the speedometer may read erratically or incorrectly. Also, the traction control and anti lock brake warning lights specific to each vehicle may be illuminated, depending on the design of those systems. You may notice the vehicle hesitate to accelerate, cruise control will not function properly, and the vehicle may not shift properly through all of the gears.

In the event that a wheel speed sensor fails, the ABS, traction control system (TCS) and manufacturer specific stability control system lights will illuminate, informing the driver that the systems are disabled. The vehicle will be more prone to tire slip, and normal driving patterns may need to be adjusted to correct for the loss of computer control. On older vehicle's, the speedometer can be affected, causing illumination of the check engine light as well.

A faulty cruise control module will simply result in deactivation of cruise control settings. This is because a detected error in the cruise control system could lead to hazardous driving conditions, so the module will be disabled, and the cruise control system warning light will be displayed. This will be a different message depending on make and model, and a warning light or message may be displayed on the driver instrument cluster.

What are the steps to diagnose the cruise control issue in a 1999 Audi A6?

To diagnose the cruise control issue in your 1999 Audi A6, start with the simplest solutions before moving on to more complex diagnostics. Begin by checking the fuse associated with the cruise control system, as a blown fuse can easily disrupt functionality. Next, inspect the cruise control buttons on the steering wheel to ensure they are operational, since faulty buttons can prevent the system from engaging. It's also crucial to examine the brake lights; a malfunctioning brake light switch can interfere with cruise control operation. If these initial checks do not resolve the issue, use an OBD-II scanner to look for error codes that may indicate specific problems within the system. Additionally, inspect the vacuum lines connected to the cruise control actuator for any leaks or damage, as these can significantly impact performance. Finally, test the cruise control module to confirm it is sending the correct signals; if it is faulty, replacement may be necessary to restore functionality. By following this structured approach, you can effectively diagnose and address cruise control issues in your Audi A6.

What are the common problems that could cause the cruise control to stop working in a 1999 Audi A6?

When dealing with cruise control issues in a 1999 Audi A6, it's essential to understand the common problems that may be at play. One frequent culprit is a faulty brake light switch, which can prevent the cruise control from engaging since it is designed to deactivate when the brake pedal is pressed. Additionally, vacuum leaks within the system can disrupt the cruise control's ability to maintain a steady speed, leading to inconsistent performance. Another potential issue is a defective speed sensor, which can provide inaccurate speed readings and cause the cruise control to malfunction. Problems with the throttle cable, such as it being stuck or damaged, can also hinder the system's operation. Lastly, electrical problems, including blown fuses or wiring issues, can significantly impact the cruise control system's functionality. By identifying and addressing these common issues, DIYers can effectively troubleshoot and resolve cruise control problems in their Audi A6.

How urgent is it to repair the non-functioning cruise control in a 1999 Audi A6?

While the non-functioning cruise control in a 1999 Audi A6 may not pose an immediate safety risk, it is still important to consider the potential implications of neglecting this issue. Cruise control, while a convenience feature, enhances the driving experience, especially on long trips where maintaining a constant speed can reduce fatigue. Ignoring the problem could lead to further complications, such as electrical issues or problems with the vehicle's speed sensors, which might affect other systems. Additionally, if the cruise control system is left unaddressed, it may become more costly to repair over time. Therefore, while it may not be urgent, addressing the cruise control malfunction sooner rather than later can prevent inconvenience and ensure that your vehicle operates at its best, ultimately contributing to a more enjoyable driving experience.

You’ve got options with RepairPal

Whether you need a more accurate auto repair estimate or help finding a reputable shop in your area, we’ve got you covered.