1998 Porsche Boxster Cruise Control Isn't Working

Diagnosing Common Issues with Cruise Control in Your 1998 Porsche Boxster and How to Fix Them

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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 1998 Porsche Boxster cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty sensor can lead to incorrect readings, causing issues with engine performance or triggering warning lights on the dashboard.
  • Control Module: A faulty control module can result in 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 acceleration and poor engine 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 1998 Porsche Boxster 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 first steps to diagnose cruise control issues in a 1998 Porsche Boxster?

When diagnosing cruise control issues in a 1998 Porsche Boxster, it's essential to adopt a methodical diagnostic approach that begins with the most straightforward checks. Start by ensuring that the cruise control button is functioning correctly; it should illuminate on the dashboard when pressed, indicating that the system is receiving the activation signal. Next, inspect the cruise control module for any visible signs of failure, as this is a common culprit for malfunction. Following this, examine the cruise control sensor and switch, as faults in these components can disrupt the system's operation. It's also crucial to verify the throttle actuation, since any problems here can directly affect cruise control functionality. Don't overlook the importance of checking Fuse #B7; a blown fuse can easily lead to system failure. If all these components appear to be in good condition, proceed to inspect the cruise control unit itself for defects. Additionally, look for any mechanical obstructions that might hinder the system's performance, such as a stuck plunger. Finally, if you experience intermittent issues, consider cleaning the electronic contacts of the cruise control stalk or switch to enhance connectivity. By following this structured approach, you can effectively identify and address the root causes of cruise control problems in your Porsche Boxster.

What common issues cause cruise control failure in a 1998 Porsche Boxster?

When diagnosing cruise control failure in a 1998 Porsche Boxster, it's essential to consider several common problems that could be at play. One of the primary issues is a malfunctioning control module, which can disrupt the communication between the cruise control system and the vehicle's engine management. Additionally, sensor or switch failures are frequent culprits; if the throttle position sensor is not functioning correctly, it can lead to erratic throttle actuation, causing the cruise control to disengage unexpectedly. Another critical area to examine is the throttle actuation system itself, as any issues here can prevent the cruise control from maintaining speed effectively. If you notice black exhaust from the tailpipe, this could indicate that the engine's computer is overcompensating due to a faulty throttle position sensor, further complicating the cruise control's operation. By systematically checking these components, you can identify the root cause of the cruise control failure and take the necessary steps to resolve the issue.

How urgent is it to address the non-functioning cruise control in a 1998 Porsche Boxster?

While the non-functioning cruise control in a 1998 Porsche Boxster may not pose an immediate safety risk, it is important to recognize that neglecting this issue could lead to more significant problems over time. A malfunctioning cruise control system can indicate underlying electrical or mechanical faults, such as issues with the control module or wiring, which may worsen if not investigated. Additionally, if you frequently rely on cruise control for long drives, its absence can detract from your overall driving comfort and convenience. Therefore, while it may not be urgent to fix, addressing the problem sooner rather than later can prevent further complications and enhance your driving experience. Taking the time to troubleshoot the system, checking components like the brake pedal switch and control unit, can help ensure that your vehicle remains in optimal condition and ready for enjoyable journeys ahead.

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