2020 Toyota Corolla Electrical Problems

DESIGN FLAW & SAFETY RISK: Toyota critically mismatched the standard battery to the vehicle's electrical charging profile; an AGM battery should be specified from the factory. Engine programming drops alternator voltage during cruising, deeply discharging the battery, and forces high-voltage surges (15V+) into it during deceleration. Because standard batteries cannot handle these rapid recharge loads during deceleration, the internal thermal load routinely overheats and boils the liquid electrolyte, even when brand new. This continuous boiling vents volatile hydrogen gas and discharges corrosive battery acid inside the engine bay. This structural flaw culminated in an immediate safety hazard when the battery physically exploded under the hood, creating a severe risk of engine compartment fire, chemical acid burns, and complete vehicle electrical blackout in active traffic. COLLATERAL DAMAGE & HISTORY: The chronic discharge and boiling of highly corrosive battery electrolyte severely damaged and corroded surrounding critical vehicle components. The acid completely corroded the transmission mount, the metal battery holder restraint, and the body paint. Furthermore, the corrosive boil-over burned off and destroyed several electrical connectors, plastic shrouds, plumbing hoses, and sections of the primary engine wiring cable harness. Since owning this 2020 Toyota Corolla, the vehicle has suffered systematic electrical degradation, requiring a full battery replacement at least once every single year. The exploded battery could not be safely retained due to its hazardous, ruptured state. WARNINGS & INSPECTIONS: No dashboard warning lamps, battery alerts, or diagnostic codes were triggered on the display prior to the physical battery failure. The rupture and electrical blackout occurred instantaneously. The vehicle has not been inspected by police or insurance representatives as no crash resulted directly from the blast.

NHTSA ID

11755366

Incident

Aug 6, 2026

The contact purchased a 2020 Toyota Corolla. The contact stated that they discovered a mileage discrepancy after the purchase. The vehicle was a private sale on Facebook market. At the time of purchase, the vehicle mileage was 52,000. It was later discovered that the vehicle’s title mileage was 132,000. The contact stated went the DMV, and he discovered the mileage 132,483.

NHTSA ID

11739330

Incident

May 20, 2026

Mileage

132,483 mi

when I use blinker windshield wipers turn on and sometimes when I call or somebody calls my cell phone I can hear them, but they cannot hear me. does not happen all the time, but I was concerned since there was a recall on certain toyota corolla that says a short circuit may develop in the OCS sensor, preventing front passenger air bag from deploying and my son who is a mechanic said both of these could be a problem with the wiring in the column and I thought it may be connected to the same recall as the air bags? the wipers coming on is happening more often these days and that is why I mentioned it to my son who is a mechanic. he will not touch it since it is still under my extended protection but he is concerned about it getting worse since the blinker is attached to the column. as far as using not being heard by callers or when I call I am concerned if I need to call in an emergency the ones I call cannot hear me. as far as when this started I do not remember but I know it's been at least 6 months if not longer, it just seems to be doing it more often lately

NHTSA ID

11714511

Incident

Jul 1, 2025

Beginning on April 18, 2025, my 2020 Toyota Corolla LE began experiencing repeated failures involving multiple safety systems while driving. Without warning, several lights illuminate at the same time, including: Brake System Malfunction, Pre-Collision System, Parking Brake System, Vehicle Stability Control, Check Engine, and Secondary Collision Brake System. These warnings appear suddenly during normal driving, then sometimes disappear, then return again unpredictably. These failures disable several integrated safety systems and create a serious safety risk due to changes in braking performance, loss of stability control, and disabled collision-avoidance functions. Diagnostic scans from both the dealership and an independent mechanic repeatedly show: P1578 — Brake System Malfunction P265B — Rocker Arm Actuator Position Sensor Circuit Range/Performance (Bank 1) Both codes reappear even after being cleared. The vehicle was with Loving Toyota Lufkin, TX multiple times over seven months. They received over $7,100 in insurance payments for repairs, $463 towing cost (due to the negligence of Loving Toyota) and almost $1,500 in rental cars (Paid by State Farm) but were unable to diagnose or fix the underlying failure. Loving Toyota also provided a courtesy rental for 7+ weeks while they did no repairs to the car. The safety warnings continue to occur. Toyota Corporate is now involved but the vehicle remains unsafe to drive. The same code P265B is present that was present back in April 2025. This car is not safe! The problem has been reproduced by me, the dealership, and an independent shop. The vehicle is available for inspection. All scans, photos, videos, and documentation are available upon request. Date first occurred: April 18, 2025 Issue continues intermittently to present day

NHTSA ID

11700972

Incident

Apr 18, 2025

This is in regards to toyota CSP 24TE04 and the Engine Bypass System. This was also included in a class action lawsuit that got dropped. Engine Bypass System is faulty and shows check engine requiring replacing of Bypass Valve and or wiring. According to 24TE04 it has been affecting over 2 million cars, but not all are being fairly covered. They need to include all models with this system that were produced during this time. Thank you

NHTSA ID

11700331

Incident

Nov 14, 2025

The contact owns a 2020 Toyota Corolla. The contact stated that after the vehicle was started, the contact started driving, and a voice message was heard coming from the speaker on the driver’s side door, stating that the communication module had failed. The vehicle was taken to the dealer, where it was diagnosed, and determined that the Data Communication Module needed to be replaced. The vehicle was not repaired due to the cost. The manufacturer was informed of the failure. The failure mileage was approximately 38,000.

NHTSA ID

11694802

Incident

Oct 8, 2025

Mileage

38,000 mi

I’m getting ENGINE MAINTENANCE REQUIRED VISIT YOUR DEALER, And it has to do with the A/C It only comes on when I turn on the A/C which has to work the “Coolant Bypass valve” I’ve looked online and many others have had issues it’s the 2020 and onward year Toyota, I’m not the only one Many have mentioned they reach out the dealer & state this is not a recall and need to pay out of pocket to fix, but with some many people having same issue, doesn’t seem right that it wouldn’t be a recall with its MULTIPLES of people having this same issue

NHTSA ID

11688004

Incident

Sep 17, 2025

The contact’s mother owns a 2020 Toyota Corolla. The contact stated that while looking in the list of features on the infotainment center, the Forward Collision, Brakes, Accelerator, Lane Assist, On-Board Collision, and other safety features were flagged as malfunctioning. The contact stated that the list of malfunctioning systems seemed to have increased over time. The vehicle failed to turn off intermittently, causing the driver to make several attempts to turn off the vehicle. The vehicle was not taken to the dealer to be diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was 80,000.

NHTSA ID

11686565

Incident

Mar 11, 2025

Mileage

80,000 mi

SOS is malfunctioning. Rebooting every thirty seconds. Interferes with handfree phone calls messages pop up asking to call for operator. Google this and it very common. The sos is for emergencies to get you help and it cuts off every thirty seconds.Your phone calls. Were the person you're talking to cannot hear you until it stops.

NHTSA ID

11685651

Incident

Jul 23, 2025

The contact owns a 2020 Toyota Corolla. The contact stated that while operating the vehicle, the message "Communication Module Failure" was activated. The cause of the failure was not yet determined. The local dealer and the manufacturer were contacted regarding the failure, but no assistance was provided. The failure mileage was 37,000.

NHTSA ID

11681365

Incident

Jun 1, 2025

Mileage

37,000 mi

after shortly pumping gas, I received a alert on my car that I needed to check my fuel cap, after checking fuel cap I proceeded to drive on the highway during this time a multitude of sensors started to go off on my car, and it started to drive weird there were light such as my interlock, being deactivated, parking, brake, deactivated, malfunction of VSC, collision deactivated. Then suddenly while driving at an accelerated speed, and trying to slow down, my engine turned itself off, and I was not able to re-crank my car. There is an active recall with Toyota for the fuel pump, which I was told by Toyota was the issue, but due to my VIN not being associated they would not repair as a recall

NHTSA ID

11657355

Incident

Apr 27, 2025

The vehicle flashes ‘connected device is not compatible’ with the ‘SOS button flashing continuously red then green.’ This message causes the microphone to remove 1 to 3 seconds of sound every 5 to 15 seconds making a clicking noise when speaking on vehicles Bluetooth. This is typically corrected by a DCM reset and firmware update. Not only is this incredibly inconvenient during normal conversation but having to repeat random portions of the conversation is irritating at best. Recently I had to make a 911 call and had to repeat myself several times to request emergency services. This glitch caused the emergency 30 second call to be extended roughly 1 1/2 to 3 minutes delaying response time. If the clicking occurs while the other person is speaking this is not noticeable. This is an identified issue only covered under basic warranty with specific TSB correction. This defect causes portions of vehicle occupants conversation to be removed and replaced with a clicking noise.

NHTSA ID

11632056

Incident

Oct 9, 2024

I am experiencing a recurring issue with the Data Communication Module (DCM) in my 2020 Toyota Corolla. This component was previously subject to a recall, which I addressed at a dealership. However, the problem persists, and many other Toyota owners, including those with RAV4 models, are reporting similar issues. Discussions on forums such as Toyota Nation and Toyota Owners Club highlight these ongoing concerns. My vehicle is out of warranty, and replacing the DCM is estimated to cost over $800. I have confirmed that the issue lies with the DCM system, as removing the corresponding fuse eliminates the error message on the multimedia system. However, this circuit also powers the right speaker and microphone, making it impractical to simply disconnect the module. The local dealership has quoted $205 for diagnostics, despite my prior identification of the problem. Revisiting the original dealership where the recall work was performed is not feasible, as it is located across the country. Toyota has not offered a remedy, leaving me without an affordable or practical solution to address what appears to be a manufacturer fault. I am seeking assistance and accountability for this persistent and widespread issue. Please look at the corresponding links detailing the systemic problem with the system, that other owners have experienced [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11627613

Incident

Nov 25, 2024

Car would not start/turn over - Not battery related. Toyota determined the ECU went bad and stated the cause was improperly jumping the battery. The issue happened randomly one day (car was driving fine previous days)

NHTSA ID

11626370

Incident

Nov 16, 2024

Vehicle would not start. After the vehicle's battery was jumped, the vehicle would start, but upon moving the vehicle, the dashboard message read, "Engine Stopped - Steering Power Low." There are numerous entries in online forums of others looking for solution for the same issue. Sometimes others have said that this occurred while in stop-and-go traffic on the highway or idling at a red light. Clearly, if a vehicle becomes disabled on a roadway with no prior warning of a failing battery, that is a safety issue. There was no warning of a failing battery. Battery was replaced, which was a surprise for a 2020 vehicle. However, this issue has occurred in newer vehicles as well if you review the comments in the online forums. Failed battery was tested and measured 67CCA/295CCA @11.44V. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11611445

Incident

Aug 20, 2024

An engine maintenance required popped up in the vehicle and was unable to be removed Took the vehicle to get checked at a Toyota dealership and they advised it was the coolant valve bypass was faulty

NHTSA ID

11584948

Incident

Apr 24, 2024

Dashboard stated engine maintenance required- visit your dealer and it turned out to be a bypass coolant valve malfunction per Toyota mechanic specialists.

NHTSA ID

11582798

Incident

Apr 7, 2024

Electrical issue on vehicle says that vehicles safety features are unavailable and all the light indications on the dash are lit up. It was taken to the dealership several times but the issue still hasn’t been resolved.

NHTSA ID

11572833

Incident

Feb 19, 2024

Around 40k miles I received an Engine Maintenance Required warning. After some research Engine Maintenance and Engine Service Required are two very different indicators. I received and P2681 code meaning the electrical coolant bypass valve had failed unfortunately one can’t tell if it’s stuck shut or open this could lead to one’s care over heating and or damaging one’s engine. After some research I’ve come to find out most 2020-2024 corollas have been having this issue tends to happen about 30-50k miles

NHTSA ID

11566170

Incident

Sep 6, 2023

I was driving on the road and I heard something like an explosion, I turned the emergency lights on and stopped to find out what had happened. I saw the sunroof completely broken, fortunately I didn’t get hurt but I got so scared and I don’t know if I will feel comfortable driving my car again.

NHTSA ID

11524407

Incident

May 30, 2023

1. First problem I had with my 2020 Toyota Corolla Hatchback SE: SAFETY RECALL 20TA07 (Backup LampsMay Become Inoperative) - 10.29.2020 2. Second problem was with the software draining the battery way too rapidly, which made me unable to start my car. I had to have a tow truck come by and he was able to recharge the battery (he knew to do that with my car instead of towing it away, because he was seeing this type of issue with this type of car a lot). I took it to my local toyota dealership and had them inspect it. They told me that they need to update the software of the vehicle and that I should not be having this problem again after. *EL1934 FIRMWARE UPDATE (5.21.2021)* 3. Third problem I had was with the temperature gauge. The needle pointer in the dash did not go up and stay in the middle between C & H. It stayed closer to C (cold). It took longer than it should have to heat up the interior of the car when I turn the heat on in the morning. I took it to my local toyota dealership and after they inspected this issue, they told me that they needed to replace the thermostat unit. *MA001 THERMOSTAT ASSEMBLY* (3.19.22) 4. Fourth problem is with the transmission. I felt jerking motions from the car when accelerating and when braking-coming to a stop. **26312 CAR JERKING UPON ACCELERATION /FOUND TRNSMISSION CODE /NEED NEW TRANS ASSY UPON INSPECTION AND HEATLH CHFCK FOUND CODE P07457F AND PO7757F SOLENOID A B BOTH STUCK OFF /REST MEMORY /NO CHANGED /FOUND NEED NEW TRANS MISSION ASSY /REMOVE AND REPLACE TRANMISSION ASSY AND PERFORM RESET AND INITIALIZATION/PERFORM HYDRULIC AND ELECTRICAL TEST /NO PROBLEM FOUND /PROBLEM AT THE TRANSMISSION ITSELF CAR JECKING UPON ACCELERATION** Transmission, Automatic - Replace* (12.10.2022) I found out online that the transmission problem was known for 2018-2020 corolla hatchbacks, but Toyota did not replace it immediately. There should be a general recall for the transmissions for these vehicles ASAP!

NHTSA ID

11496954

Incident

Dec 10, 2022

The contact owns a 2020 Toyota Corolla. The contact stated that while driving at an undisclosed speed, the vehicle emitted an abnormal slushing sound. There was no warning light illuminated. The contact stated that upon parking and inspecting the vehicle, he noticed that the abnormal sound was coming from the front driver's side door. The contact then moved each door of the vehicle from side to side and noticed that the failure occurred on the front passenger's side door and the front and rear driver's side doors. The vehicle was taken to the dealer on several occasions and the water was drained from the doors; however, the vehicle was not diagnosed. The manufacturer was notified of the failure and informed the contact that they would cover the repair of the vehicle. The contact stated that it had been two months and the vehicle had not been diagnosed or repaired. The contact stated that he was concerned for his safety as he was a disabled veteran. The failure mileage was approximately 85,000.

NHTSA ID

11489938

Incident

Aug 19, 2022

Mileage

85,000 mi

Battery and alternator died causing power steering to fail and wheels to lock up. Should not happen on a car this new, brought to dealer and charged me $740 to fix it.

NHTSA ID

11486344

Incident

Sep 26, 2022

Mileage

60,000 mi

DOORS FILL UP WITH RAIN WATER AND WATER IS SLOSHING AROUND INSIDE DOOR FRAME. NEED DOORS REPLACED DUE TO ELECTRICAL COMPONENTS BEING DAMAGED BY MOISTURE CORROSION.

NHTSA ID

11485436

Incident

Sep 20, 2022

Newly bought vehicle won't start when key is turned in ignition. Problem is a repeat problem and vehicle was repeatedly towed to dealer (Gosch Toyota). Dealer said there is nothing wrong with the car . Dealer admits he can't reproduce the problem and paperwork I've obtained from them indicates they may not have even tried. Car has major safety issue and is unreliable which is an explanation falling on deaf ears at Gosch. So it remains parked in my driveway. I refuse to put anyone in my family into it because of obvious safety issues. Car is totally unreliable if one can't rely on it to work .

NHTSA ID

11462398

Incident

May 15, 2021