2020 Honda Civic

I am writing to file a complaint regarding the air conditioning system failure in my 2020 Honda Civic Sport. The air conditioner in my vehicle began blowing hot air instead of cold air starting in January 2024. I took the vehicle to a mechanic for inspection, I was informed that the evaporator has failed and needs to be replaced. While researching this issue, I discovered that many other Honda Civic owners have reported similar air conditioning problems involving the evaporator and AC system. I also became aware of a 2021 letter involving American Honda Motor Co. and Honda dealership personnel regarding evaporator leaks in vehicles with VIN numbers beginning with 2HG or 19X. The letter stated that Honda was researching these vehicles in an effort to better understand the issue. Given the number of similar complaints and Honda’s apparent awareness and investigation into evaporator leaks, this appears to be a potentially widespread defect affecting these vehicles, even when properly maintained. The failure of the air conditioning system has caused significant inconvenience, medical issues and financial burden. I have severe Hyperthyroidism, and reside in CA. Due to extremely hot weather & no A/C, the heat affected my heart rate and health severely. My honda is utilized daily for employment & commitments. Without proper air conditioning in almost 3 years now, while driving my car, I was admitted into the hospital last summer 2026 for 5 days due to the extreme heat affecting my heart and almost causing me to go into a coma aka [thyroid storm]. I believe this issue should be investigated further, as it may indicate a defect in the vehicle’s air conditioning system. I respectfully request that the NHTSA review this matter and investigate whether the evaporator failure in the 2020 Honda Civic Sport is a recurring manufacturing defect that may warrant further action or assistance for affected vehicle owners. Thank you for your time and attention to this matter.

The turbocharger bypass control solenoid valve circuit on my 2020 Civic Si has developed an intermittent open, setting DTC P0035. I diagnosed it myself: the solenoid coil measures 45 ohms and functions when commanded via bi-directional scan tool, and supply voltage is present at the harness connector. However, the control circuit reads approximately 9V in the off state when it should be near ground, and the reading fluctuates when the harness is flexed near the connector — indicating a partial break in the wiring consistent with vibration fatigue. This is a safety concern because the ECM fault cascades to other systems. My scan report shows U0401-68 in the ABS module and U0416-68 in both the EPS and Integrated Driver Assistance modules. The result is that VSA stability control is disabled. I first noticed the problem because warning lights appear during hard cornering — precisely when stability control is most needed. Honda has acknowledged this exact failure mode. Service Bulletin 18-044 (NHTSA ID 10142655), issued June 2018, covers the 2017 Civic Type R for DTC P0035 and states the cause as: heat and the natural frequency of the harness cause the coupler wire to oscillate, producing an open circuit to the turbocharger bypass control solenoid valve. The remedy was a replacement engine wire harness kit. The Si shares the same L15B7 engine family and the same bypass control solenoid circuit, but no campaign covers it. Owner forums document numerous P0035 wiring failures on non-Type-R 1.5T Civics. I am requesting that NHTSA consider whether this defect and its effect on stability control warrants a safety investigation and expansion of the existing remedy to other 1.5T Civic models.

The contact owns a 2020 Honda Civic. The contact stated that while driving at an undisclosed speed, the compressor shaft failed, and the shaft seal caused further damage to the compressor and caused an additional failure. The contact associated the failure with Technical Service Bulletin: 23-039. The dealer was contacted and diagnosed the vehicle with compressor failure. The vehicle was not repaired. The manufacturer was made aware of the failure and stated that the warranty only covered the shaft seal and not the compressor. The failure mileage was approximately 166,000.

The contact owns a 2020 Honda Civic. The contact stated that while driving at an undisclosed speed and making a turn, the headlights failed to operate properly and failed to provide adequate illumination while driving. The dealer was contacted, and headlight failure was repaired; however, headlights were not recalibrated. The manufacturer was not made aware of the failure. The failure mileage was approximately 76,000.

The contact owns a 2020 Honda Civic. The contact stated that while driving at highway speeds, the steering wheel was sticking with resistance while turning the steering wheel to the left. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure, but no assistance was offered. The contact was informed that the vehicle was not under a recall associated with the failure. The failure mileage was 120,000.

on 7-28-26 After filling my vehicle with gas at the next red light, all lights on dashboard went on flickering warning (Christmas tree effect). on 7-29-26 After researching online Roadside came out and did Battery and alternator test that passed. I did hard reboot from instructions I found online and after several attempts the lights cleared twice, the morning of 7-30-26 when leaving for work the flickering lights came back on. Vehicle had a slight tremble but cleared after a few seconds while vehicle warmed up. I went to get the battery checked at the shop and it passed also had air filter changed. Lights still on, car is running fine, but I feel unsafe to drive and have an appt at the dealer for a diagnosis check on 7-31-26.

The A/C went out on this vehicle. The A/C only worked half way in the car. It would only cool the passenger side and not drivers side. When I took it in to get it fixed, they said it was the condenser. There was a recall for the compressor shaft seal but not the condenser. They replaced the condenser and compressor shaft seal. As I checked the Internet I found a recall for this problem in Canada but not in the U.S. I asked Honda about it. They said it was VIN specific right now unless enough people complain about this problem. If it happened in Canada it should be dealt with here. According to my search there are others in the U. S.that have had this problem. How many complaints does it take before this is dealt with?

At least a half dozen times the car would brake automatically when nothing was in front of the car. The BRAKE warning light would appear on the dashboard as the car abruptly slowed down. The car slowed down but never came to a complete stop. This happened at various speeds. Once on the freeway at high speeds, 3 times just before an intersection where I had a green light and other various times. I brought the car to 2 different dealers. They could not replicate the problem so they said there was nothing they could do. The courtesy car driver who gave me a ride said they occasionally experience the same thing in the courtesy car.

On passenger side, 4 of 5 wheel hub bolts (lug bolts) broke off during driving. The lug nuts did not come loose. The bolts actually broke off with lug nuts attached. This caused the wheel to separate from the car while driving. This caused an accident and $5,500 damage to the car. There were no warnings from the in-car information center.