1991 Toyota MR2 Cruise Control Isn't Working

Diagnosing Common Issues with the Cruise Control System in Your 1991 Toyota MR2 and How to Fix Them

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Reviewed by
Devin Cabugcal
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 1991 Toyota MR2 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 1991 Toyota MR2 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.

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 1991 Toyota MR2?

To effectively troubleshoot the non-functional cruise control in your 1991 Toyota MR2, start with the simplest checks before moving on to more complex diagnostics. Begin by inspecting the fuse box for any blown fuses related to the cruise control system, as a blown fuse can easily disrupt functionality. Next, examine the cruise control switch located on the steering wheel to ensure it is operational; a faulty switch can prevent the system from engaging. Following this, check the vacuum hoses connected to the cruise control actuator for any signs of leaks or damage, as these can significantly impact performance. It’s also crucial to test the cruise control actuator itself to confirm it is receiving power and functioning correctly. Lastly, ensure that the throttle cable is properly adjusted and not interfering with the cruise control operation. By systematically addressing these areas, you can effectively diagnose and potentially resolve the issues affecting your cruise control system.

What are the common problems that could cause the cruise control to stop working in a 1991 Toyota MR2?

When dealing with a malfunctioning cruise control system in a 1991 Toyota MR2, it's crucial to understand the common problems that could be at play. One of the first things to check is the fuse; a blown fuse can easily disrupt the entire system. If the fuse is intact, the next step is to inspect the cruise control switch, as a faulty switch may prevent the system from engaging or disengaging properly. Additionally, vacuum leaks can significantly impact the cruise control's ability to maintain speed, so examining the vacuum lines for any signs of wear or damage is essential. Another critical component to consider is the speed sensor; if it is malfunctioning, it can lead to inaccurate speed readings, causing the cruise control to fail. Furthermore, issues with the brake light switch can interfere with the system's operation, as it is designed to disengage when the brakes are applied. Lastly, don’t overlook the throttle cable; if it is not functioning correctly, it can hinder the cruise control's ability to maintain the desired speed. By systematically checking these components, you can effectively diagnose and address the cruise control issues in your MR2.

How urgent is it to address the non-functioning cruise control in a 1991 Toyota MR2?

Addressing the non-functioning cruise control in a 1991 Toyota MR2 is crucial for several reasons. First and foremost, cruise control enhances driving comfort by allowing the driver to maintain a steady speed, which is particularly beneficial during long highway trips. When this system fails, it not only diminishes the convenience of driving but may also signal deeper issues within the vehicle's electronic or engine control systems. Ignoring these symptoms can lead to more significant problems, potentially affecting the overall performance of the car. Moreover, a malfunctioning cruise control system could pose safety risks, especially if it is linked to critical components that influence vehicle operation. Therefore, it is essential to prioritize the repair of the cruise control system to ensure both safety and optimal performance, preventing further complications that could arise from neglecting the issue.

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