The Transmission Control Module (TCM) has gone out on my car, causing it to shift to 2nd gear while doing 75mph with cars around me, and would no longer shift out of 2nd gear, or into reverse. It was an extremely dangerous situation that made me come very close to wrecking into a car, as well as the many cars behind me that had to emergency brake due to my rapid deceleration, especially without and brake lights coming on because it was engine braking. Doing a simple google search show that this is an extremely well-known problem effecting almost every Mazda 3 that used this TCM in 2010-2011. Any mechanic will tell you it's a known problem, and that it was due to where and how Mazda placed the computer, which causes it to overheat and fail without warning. I'm not sure why there has not been a recall on this issue with how prevalent it has been, and how easily recognized it is by mechanics. It is not a cheap fix, and can cause many other major issues leading up to requiring a full new transmission, if the problem did not already cause the car to wreck!

- Lenoir City, TN, USA

Has I was driving my car home from work. Driving about 35mph I started to loose power and then the at, engine, tcs/dsc lights all came on. When I made it home I let it sit. While I looked into the issue on google later that evening I went back to see if my car was still having the issue. I placed the car in reverse and my car jumped/ jerked real hard. As I let go of the break I noticed my car didn't slowly move on its own like prior. I actually had to press the gas down quite a bit. My car revved up to 3 making a loud noise. The car had no power would hardly move. As I researched the problems and light issues it was kinda a surprise how easy it was to figure out what the issue was. Since this is a very very common issue found with the Mazda cars. So many people have this issue that when you order the part at over $600 in the directions that is sent they actually recommend relocating the tcm to a different location using zipties. Went to have car codes read on my car informed the guy what I believed it to be and the most likely will be U0101 lost communication with tcm, and I was correct.

- Fontana, CA, USA

The check engine light came on and the car began stalling as I drove on the freeway. It stalls and feels like it won't change gears. Took it to a shop and they kept telling me the computer code was not giving them any information and they couldn't figure out what was wrong with it.

- Phoenix, AZ, USA

10+ incidents of sudden unintended acceleration since Aug 2018. Always at freeway speed of traffic, I.e. 70-75mph. Occurs when intentionally decelerating (easing off the gas pedal and initiating braking). Rpms jump to 7 or 8. acceleration immediately drops and steads after tapping/applying pressure to brakes. Has been taken ralph thayer dealership 3 times -- aug2018, jan2019, feb2019. Each time vehicle kept for a week but unable to duplicate issue. Data recorder was installed in jan2019. Despite a several minute long episode on Feb 22, 2019 in which the car behaved erratically (buckling and jolting) and wouldn't accelerate more than 60 mph while the rpms were high (4-5) for several minutes, this was somehow not sensed by the data recorder. My own guess is an issue with the PCM or the automatic transmission control module. Have suas affected transmission? seems to be a known issue yet the dealer/Mazda reaction is perfunctory at best. No commitment to resolve. E.g. because my driving was limited while the recorder was in, I requested that it be left in for 3 months. Mazda refused, stating that if it happens again (and it will), they'll reinstall the recorder. That a collision hasn't happened is just luck. A serious accident caused by this vehicle is imminent since these issues adversely affect the ability to control the vehicle. I also don't relish being my own crash test dummy. There is nothing they can do beyond a series of expensive parts replacements based on their guesses? I have some video and photos per their request, but note that attempting to photograph or video the dashboard while driving is an extra bullet in what already feels like russian roulette. I've attached a summary of events provided to Mazda in January and the most recent mechanic's report. $800 suggested for guess-based tcm replacement, $240 inconclusive tests, no loaner provided.

- Detroit, MI, USA

I was driving and felt the car down shift on the highway, at light came on and some sort of traction control light came on. RPM would go crazy sometimes while this happened. When I got home and put it on park it shifted really hard tried to put it on drive and shifted hard. As well so I let it be. I heard about this happening to other Mazda as well please investigate this supposedly its a issue with the transmission control module.

- East Hartford, CT, USA

Gas pedals is sticky when flooring it. It will stay at the maximum acceleration position forever or the gas pedals is stick with the floor forever. The only way to get out of it is to manually pull it back. The sticky gas pedals will lead to unintended acceleration incidents. I believed this is a common issue with year 2010 Mazda3 5 door.

- West Roxbury, MA, USA

Drove 80 miles to destination on freeway using cruise control. Car accelerated above cruise setting on downhill - did not engine brake to hold speed. When pulling into destination hotel parking spot and with right foot on brake, engine revved dramatically. Applied both feet to break. Automatic transmission. Changed gears to N, R & P, but engine continued to rev. Turned engine off. Smoke generated from engine entered cabin. Did not use car until next day. Returning home next day used cruise control and exited freeway for break. Slowing down for stop light with car ahead and foot on brake when engine revved again as before. Shifted car into neutral and turned off car then back on. Drove car to dealer on way home without another incident. This dealer is where we purchased the care and all work except tires/alignment and battery occurred. They examined and inspected the car and kept it for the next 10 days logging 200 miles without a recurrence of the unintended acceleration.

- Portland, OR, USA

The contact owns a 2010 Mazda Mazda3. The contact stated that the cruise control sensor illuminated. The vehicle was not inspected or diagnosed. The VIN was not available. The manufacturer was notified of the. The approximate failure mileage was 90,000.

- Hewitt, NJ, USA

Many times but sporadically over the last two years my Mazda 3, when coming to a stop and foot firmly on the brake will have a sudden surge in RPM between 1200-2500 RPM and try to accelerate. Seems to happen most often first thing in the morning more often. Because I am constantly ready there has been no crash, though the time rpms reached 2500 I had difficulty stopping the car, on a freeway on ramp where sudden deceleration was needed. I have found that one pump of the break alleviates the problem if there is room to do so.

- Renton, WA, USA

On 2 occasions I was completely stopped, for a red light and stop sign, when the engine revved on its own and the car lurched forward. Felt like I was pushing brake pedal through the floor to stop it but it recovered on its own after several seconds. Very scary. I am afraid of hitting a car or someone. At the Mazda dealer now and has been for a week as they try to find out the problem.

- Spencerport, NY, USA

The contact owns a 2010 Mazda3. The contact stated that while the vehicle was idle, it would lunge forward and the rpms would increase. The failure occurred intermittently. The contact was forced to push the shut off button to stop the vehicle from moving forward. The vehicle was taken to an authorized dealer who could not duplicate the failure. The vehicle was not repaired. The manufacturer had not been notified. The VIN was unavailable. The current mileage was approximately 14,000. The failure mileage was 600.

- Bristol, NH, USA

On 11/4, I was on my way to meet my yoga classmate for lunch at 1917 bistro. The restaurant's parking lot was full. So, I backed out and circled the block to find another parking space. When driving on livernois I noticed a parking lot that's why I decided to go back around. I pulled into the first empty parking lot which I thought was better than trying to parallel parking in the one space on the street. So, I turned into a graveled parking lot. I made a left then began to pull up to the parking space but the car accelerated and smashed into a building. The car would not stop so I shifted the car into reverse. The car jerked back wildly; it was hard to handle but I got the car to stop. A man came out of the wig shop. I was standing outside of the car examining the damage - white paint from the building and a slight puck on both sides of the bumper. The man looked at me incredulously because he said the impact shook theshop. His mouth was open and it took him a few minutes to close it. A woman came out also because she felt the impact in the shop next to the man's shop. There were no witnesses to my acceleration problem. I did not report the incident because I did not see a police officer (it's detroit). After lunch, I drove back home and sent Mazda an email. I heard from Mazda Friday morning. The car was towed to the dealer in troy. I spoke to amir about the incident and told him that the car was on its way into the dealership (by the way, I even have my oil change at the dealership). When the car arrived I received a call from scott bryant who, in an accusatory manner asked me to repeat what happened despite amir telling him my story. He warned me that it will take all afternoon to look at the car. Scott called later to inform me that a field engineer will be coming in on Monday to look at the car. He did not offer me a rental.

- Detroit, MI, USA

Cruise control turns off when going down hills, even small ones. I use my cruise control daily and my drive to work contains many small hills. When cruising at 70, I go down a hill. The cruise control backs off then at the bottom of the hill, it fails to engage. Once I have drifted from 70 mph down to 60 mph, it turns itself off. I've had my car 2 months and this has happened 11 times now. The dealership claims there isn't anything wrong and the only way it can turn itself off is if I touch the brake or the clutch. I am doing neither. When on a busy highway, and this begins to happen, the people behind you get very angry. Beside the fact I have begun slowing down without my brake lights coming on. There are others with the same problem here mazda3revolution.com/forums/2010-mazdaspeed-3-news-discussion/2758-anyone-having-cruise-control-issues.html.

- Lawndale, NC, USA

I was stopped with the car running in drive and stepping on the brake pedal only, when the engine began revving uncontrollably. This resulted in increasingly high rpms, and it felt as if the car was about to lurch forward. I ended up turning off the car, and re-starting it. This is an intermittent problem that has happened a total of 3 times, each time while in a stopped position. I purchased the car the end of March 2010. First occurrence happened prior to 6/3/10, and the third, most recent occurrence, happened on 8/26/10. Mazda has installed a data recorder to attempt to record the problem, but now they want to remove it before the problem has re-occurred.

- Seattle, WA, USA

While driving slowly through a community center parking lot, the automobile suddenly accelerated and did not respond to braking, resulting in a crash into a brick wall.

- Arlington, VA, USA