BMW 840i Gran Coupe Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your BMW 840i Gran Coupe 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
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25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a BMW 840i Gran Coupe 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 BMW 840i Gran Coupe 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.

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.

The cruise control switch can cause complete failure of the cruise control feature, but in a lucky scenario only partial functionality will be lost. This means that the cruise control may come on, but that it will not increase in speed automatically, or the cancel button does not work leading the driver to cancel cruise control with the foot brake. In some vehicles, the cruise control light may illuminate, or a warning message may be displayed due to lack of functionality.

Troubleshooting Cruise Control Issues in a BMW 840i Gran Coupe

When troubleshooting cruise control issues in your BMW 840i Gran Coupe, it's essential to adopt a systematic diagnostic approach. Start by checking the simplest potential causes, such as a blown fuse, which is a common culprit for cruise control malfunctions. If you discover a blown fuse, replacing it could resolve the issue quickly and easily. Next, inspect the brake pedal switch, as a malfunction here can also disrupt cruise control functionality. If these initial checks do not yield results, consider examining the throttle control system and the ABS, as problems in these areas can affect cruise control performance. Should the issue persist, it may be indicative of more complex problems, such as those related to the Electronic Motor Load (EML) system, particularly if the EML light is illuminated on your dashboard. In such cases, consulting a professional technician is advisable for a thorough diagnosis and repair. Additionally, leveraging resources like RepairPal and online forums such as Bimmerforums can provide valuable insights and support from fellow BMW enthusiasts, helping you navigate the troubleshooting process effectively. By following this structured approach, you can efficiently identify and address the underlying issues affecting your cruise control system.

What Could Cause the Cruise Control to Malfunction in a BMW 840i Gran Coupe?

When dealing with cruise control malfunctions in a BMW 840i Gran Coupe, it's crucial to understand the common problems that may arise. One of the first indicators of an issue is often a warning light on the dashboard, signaling that the vehicle's system has detected a fault. A frequent culprit behind cruise control failure is a malfunctioning brake pedal switch; since the system is designed to disengage when the brake is applied, any failure here can prevent cruise control from activating. Additionally, electrical issues, such as faulty wiring or poor connections, particularly with brake light bulbs, can disrupt the cruise control functionality. Furthermore, problems with the control module, sensors, or throttle can also lead to operational failures. By identifying these potential issues, DIY enthusiasts can take the necessary steps to troubleshoot and resolve cruise control problems effectively, ensuring a safer driving experience.

Why is the Cruise Control Not Working in a BMW 840i Gran Coupe?

When your BMW 840i Gran Coupe's cruise control fails, it's crucial to address the issue promptly to avoid potential safety risks and further damage to your vehicle. One of the primary culprits could be failed or dirty speed sensors, which are vital for the cruise control system's communication with the car's computer. Neglecting to clean or replace these sensors can lead to erratic vehicle behavior. Additionally, a blown fuse dedicated to the cruise control system can render the entire feature inoperative; this is a simple fix but often overlooked. Another critical component to inspect is the brake pedal switch, as a malfunction here can inadvertently disable cruise control, impacting your driving experience. Lastly, issues with the throttle control system or the ABS can also disrupt cruise control functionality. By diagnosing these components early, you can ensure your vehicle remains safe and reliable on the road, preventing more significant issues down the line.

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