1994 Audi 90 Cruise Control Isn't Working

Diagnosing Common Issues with the Cruise Control System in Your 1994 Audi 90 and How to Fix Them

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Reviewed by
Bo Fader
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 1994 Audi 90 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 1994 Audi 90 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 throttle position sensor fails, the engine's computer tends to overcompensate with fuel, leading black exhaust coming from the tailpipe. There is a strong possibility of engine misfires, and the check engine light will come on.

Throttle position sensors can also develop "dead spots," or certain places along the throttle curve where it doesn't get a reading. When this happens, the above symptoms can occur but then stop when you further press or let off the gas pedal.

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.

What are the initial diagnostic steps to troubleshoot the non-functional cruise control in a 1994 Audi 90?

When faced with a non-functional cruise control in a 1994 Audi 90, it's important to adopt a systematic diagnostic approach. Begin by checking the fuse associated with the cruise control system, as a blown fuse is a common and easily fixable issue that can halt its operation. Next, inspect the cruise control switch to ensure it is functioning properly; a faulty switch can prevent the system from engaging. The brake pedal switch is another critical component to examine, as it is designed to disengage the cruise control when the brakes are applied. If this switch is malfunctioning, it could be the reason for the cruise control failure. Additionally, review the vehicle speed sensor, which is essential for the cruise control system to operate correctly; a malfunction here can lead to significant issues. It's also wise to check for any vacuum leaks in the cruise control system, as these can disrupt its functionality. Lastly, using a diagnostic scanner to check for error codes can provide valuable insights into any underlying problems affecting the cruise control system. By following these steps, you can effectively troubleshoot and potentially resolve the issues with your Audi's cruise control.

What are the common problems that could cause the cruise control to stop working in a 1994 Audi 90?

When dealing with cruise control issues in a 1994 Audi 90, it's essential to understand the common problems that may arise. One frequent culprit is a faulty cruise control switch, which can hinder the system's ability to engage or disengage as intended. Additionally, a blown fuse can disrupt the electrical flow, rendering the cruise control inoperative. Vacuum leaks are another significant concern, as they can interfere with the system's functionality by affecting the pressure needed for operation. A defective speed sensor may also lead to inaccurate speed readings, causing the cruise control to malfunction. Furthermore, the brake light switch plays a crucial role; if it fails, the cruise control may not engage due to safety protocols. Lastly, issues with the throttle cable can prevent the system from maintaining a steady speed. By identifying and addressing these common problems, DIYers can effectively troubleshoot and restore the cruise control system in their Audi 90.

How urgent is it to address the non-functioning cruise control in a 1994 Audi 90, considering potential safety risks and further damage?

When faced with a non-functioning cruise control in a 1994 Audi 90, the urgency to address the issue cannot be overstated. A malfunctioning cruise control system can lead to unexpected vehicle behavior, such as sudden acceleration or deceleration, which poses significant safety risks, especially in high-traffic situations. Moreover, if the cruise control fails to disengage, it can result in a loss of control, increasing the likelihood of accidents. Beyond immediate safety concerns, neglecting this issue can lead to further complications within the vehicle's electrical system or engine, potentially resulting in more extensive and costly repairs down the line. Therefore, it is crucial for DIY enthusiasts to prioritize diagnosing and fixing the cruise control system promptly. By doing so, not only can they ensure their own safety and that of others on the road, but they can also prevent the escalation of the problem, maintaining the overall reliability and performance of their Audi 90.

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