2015 Ford Mustang: adaptive cruise control problems

Filed Jul 21, 2024 · Acceleration, Brakes · CA

Hi, I was driving on the freeway and suddenly my car stopped accelerating. I would push the acceleration pedal but it wouldnt speed up. And for a few times it would speed up very much. This was very rapid fluctuation. I also noticed that the cruise control was not working. This was very scary being on the highway with this kind of speed fluctuation. After i came back home, i noticed that the brake light wouldnt turn off at all. After doing some research i found that the brake light switch broke and the car was sensing that the brake was being applied and hence was doing acceleration fluctuations. I also found out that there are many other same vehicles which has the same issue.

Filed Oct 13, 2022 · 41,000 miles · MI

The contact owns a 2015 Ford Mustang. The contact stated that while driving, the cruise control was set to 75 mph when he heard a loud noise and started to see a light then dark gray cloud of smoke at the hood of the vehicle. The contact stated that the engine started to decelerate, and he was able to coast off the road. The contact stated upon inspecting under the hood of the vehicle, oil was scattered throughout. The vehicle was towed to the dealer where it was diagnosed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and the contact was advised to call the federal safety agency Hotline. The failure mileage was approximately 41,000.

Filed Aug 5, 2022 · Acceleration, Brakes · 54,000 miles · NC

The contact owns a 2015 Ford Mustang. The contact stated that the vehicle was repaired under the federal safety agency Campaign Number: 22V011000 (Service Brakes, Hydraulic); however, while driving with the cruise control activated, the brake pedal was depressed but instead the vehicle accelerated and failed to stop as needed. The contact stated that an excessive amount of pressure was needed to depress the brake pedal while stopping the vehicle. The contact stated that the failure only occurred while the cruise control was activated. The contact had taken the vehicle to the dealer and the mechanic was also able to duplicate the failure. The dealer diagnosed that the cruise control had malfunctioned and caused the brakes to not operate as needed to deactivate the cruise control. The dealer replaced the cruise control switch; however, the failure persisted. The manufacturer was not made aware of the failure. The approximate failure mileage was 54,000.

Filed Sep 21, 2021 · Lights · GA

Traveling on highway using cruise control at posted speed limit. Approached slowdown due to accident and applied brakes. Accelerated to limit (manually) after passing accident. I was in middle lane. Vehicle abruptly began to decelerate. Continuous pressure on gas pedal did not increase speed, so I put on hazards and moved to slow lane. No failures on dashboard and quick scan through gages did not identify an issue. Re-applied pressure to gas pedal wanting to get to next exit. Car sped up, but when approaching 50 mph, it decreased again. Found that pumping gas would allow me to maintain highway speed. Pulled into truck stop at exit and turned car off. Message on console "Hill start assist not available". Let vehicle rest 15 minutes, added gas. Quick web search seemed to point to problem with ABS sensor. Seemed to drive ok in parking lot and road leading to highway ramp. Decided to try to get closer to home. Problem occurs immediately after climbing to 50 mph. Cruise control won't work. By carefully monitoring speed and pumping gas into overdrive when needed, I was able to get home. Could not get appointment with dealership until late afternoon next day. Hill start assist message comes on again when stopping. After arriving home and parking in garage I went inside for about 30 minutes. Needed to unload items from car and went back to garage noticing that the strip of lights above trunk are still on. Got back in car, started it (got hill assist message), turned lights on/off and turned off car. Now my rear brake lights are also on. I had seen a post about this, so unhooked battery to prevent drain. Next morning, reattached battery and had same problem. After more internet investigation, Awesome humans who have also had this dangerous issue and provided a $5 fix instead of a $500+ dealership fix. https://www.mustang6g.com/forums/threads/brake-light-switch-near-pedal-failure.122100/pag SUDDEN UNEXPECTED THROTTLE CAUSING SLOWDOWN ON BUSY INTERSTATE IS LIFE THREATENING.

Filed May 29, 2021 · Lights · AL

The brake light switch function was inhibited due to the plastic retainer mounted on the pedal assembly. The plastic retainer had become brittle and caused it to come apart in pieces. The retainer acts a point of contact for the brake light switch plunger which signals to the ECM when the driver is applying or not applying the brakes. Symptoms of failure are constant illumination of rear brake lights with vehicle on or off. Disables cruise control. Also most importantly it limits throttle control by reducing throttle range spraticly. No driver warnings or lights are displayed or illuminated on the IPC. Problem has been verified and reproduced by independent service center.

Filed Sep 14, 2015 · Acceleration · 3,000 miles · MI

The above vehicle is a 2015 ford mustang eco-boost convertible. It is equipped with adaptive cruise control. When a vehicle in front slows below a set speed or a vehicle cuts the car off the adaptive cruise control slows the car down, or stops it, to keep a predetermined distance. According to ford the slowing is done by the engine and not the brakes. Once the vehicle slows, and it is safe, it begins to accelerate back to the set cruise control speed. The slowing, not being done by the braking system, does not activate the brake lights. Only when the brake pedal is stepped on will the brake lights come on which also would disengage the cruise control. We have had a couple of incidents in which the vehicle behind does not see the car slowing, by brake lights, and closes at a rapid speed on the rear of the car. Looking at a dodge ram closing, not knowing it's going to stop, can be a bit unnerving. I have recently read that the automatic braking may be installed on future vehicles as a standard option. I can't imagine that keeping a vehicle from crashing into a forward moving vehicle is any more or less important then being struck in the rear because brake lights don't come on. I am certainly more cautious driving the adaptive cruise control on because of this safety issue. I have talked to ford "customer relations dept" who weren't sure how to follow this up but to sent it up the ladder. I have a ford case #cas-7876013. ...updated 12/29/15 *bf according to ford, the slowing is done by the engine and not the brakes. Once the vehicle slows down, and it is safe, it begins to accelerate back to the set cruise control speed. The slowing not being done by the braking system, does not activate the brake lights. Only when the brake pedal I stepped on will the brake lights come on which also would disengage the cruise control. The consumer stated on several occasions, other vehicles did not observe him slowing down because the brake lights did not illuminate. Updated 12/31/15.

Filed Apr 24, 2015 · Body, Electrical · 9,345 miles · IL

I was on the interstate traveling south with cruise control on. I went over a bump that I usually go over when headed in that direction and the driver door all of a sudden opened/unlocked itself. It was locked or else the dashboard would of indicated that my transmission was not in park before setting off on my trip.