2021 Toyota Tacoma Problems

What owners report

Complaints on this model year cluster around two themes: drivability concerns, reported at low mileage, where owners describe unintended acceleration, surges, rough running or stalling; and a plastic rear coolant bypass valve that leaks and can lead to overheating, often in the 50,000-75,000 mile range. Many complaints come in during the first 1,000-10,000 miles. Some brake and forward-collision complaints describe sudden or unexpected braking behavior, and a group of owners report rear differential noise.

1. 1
   Engine

   Unintended acceleration, surging and stalling

   • 14 complaints (17%)
   • median 4,500 mi at 0.4 yrs old (4 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2021–2026

   Owners describe the truck accelerating on its own at highway and residential speeds, revving up or lunging during a downshift, and in some cases not responding when the pedal is pressed. Some complaints describe the engine surging from idle to several thousand rpm and others describe stalling or rough idling with check engine and traction lights, sometimes while in cruise control on hills. Several owners say dealers could not duplicate the concern; others were told it was bad fuel or were given a misfire diagnosis. Reported from a few hundred to about 8,000 miles in many cases, though also at higher mileage.

   What to check: Drive the truck at steady highway speed, in stop-and-go traffic and up a grade, and note any surging, hesitation or delayed throttle response. Ask the seller whether the dealer has documented any throttle or misfire diagnosis.

   2 excerpts from owner complaints in NHTSA records

   “in traffic engine surges at times,going from 1200 to 3500 rpm's very dangerous, afraid to drive , wife refuses to drive it, naturally the dealer says NO PROBLEMS, that truck will last 300.000, at 3000 miles in seven months ,thinking about trading it in, dealers tell me I must repair the engine knocking noise, I didn't tell them about the revving up part, very unhappy ,have owned Toyota's never had problems !!”

   NHTSA complaint #11449441, filed 2022-01

   “After I purchased my 2021 Toyota Tacoma TRD Sport with 4 miles on it and at 1,332 miles on 11/26/21, the Check Engine light with Traction Control Off light came on while I was driving. I immediately pulled over and on the truck media screen it read this: A malfunction in the electronic control of the engine, throttle or automatic transmission has been detected. Contact your Toyota dealer and have your vehicle inspected. The truck was rough idling and had no acceleration. …”

   NHTSA complaint #11733332, filed 2026-04
2. 2
   Forward collision avoidance

   Forward-collision system warns or brakes unexpectedly

   Mentioned in 8 of 60 sampled complaints

   Owners report the pre-collision warning and automatic braking engaging with nothing in front of the truck, sometimes while using cruise control, including cases where the truck braked hard enough to skid. Other complaints describe the system failing to warn or brake in a real closing situation, and some owners say a PCS or VSC malfunction message appeared. Several owners say dealers could not reproduce the condition; the complaints refer to multiple functions of the system rather than a single component. Spread from delivery mileage to several thousand miles; often reported during highway and cruise-control driving.

   1 related service bulletin

   What to check: With the seller's permission, test drive at highway speed with cruise control set and on an open road to see whether the truck warns or brakes without cause; ask whether the sensor and camera have been recalibrated or the system serviced.

   2 excerpts from owner complaints in NHTSA records

   “I purchased a new 2021 Toyota Tacoma in december 2021 with a pre collision safety system. Less than 2 months later, my daughter was in a front end collision accident (daughter at fault). The system did not do what it was suppose to, which was warn her and help her apply the brake. At the repair center, I asked them to check the pre collision safety system. They took the vehicle to bert ogden Toyota to have the vehicle checked out. They told me the system was probably off or not set sensitive enough at the time of the accident. …”

   NHTSA complaint #11403765, filed 2021-03, 1,000 miles

   “Firestone Destination Le2 P245/75R16 On February 20, 2021 just 15 days after I purchased my brand new truck the rear passenger side tire dramatically exploded while I was driving in to my neighborhood. I was traveling at approximately 35 mph when out of nowhere a sound similar to a shotgun interrupted my driving and immediately forced me off the road in between two trees. I was narrowly missed by oncoming traffic and scared for my life. …”

   NHTSA complaint #11568254, filed 2024-01
3. 3
   Engine

   Coolant bypass valve/pipe leak at rear of engine

   • 7 complaints (9%)
   • median 76,000 mi at 4.7 yrs old (2 state mileage, few)
   • filed 2024–2026

   Complaints describe a plastic coolant bypass valve or crossover pipe at the back of the engine cracking or seeping, with low coolant in the reservoir, a sweet or chemical smell and steam or smoke from the engine bay. Some owners report overheating, a radiator that cracked afterward, or coolant loss that recurred after topping off. According to the complaints, dealers confirmed the leaking valve; some owners say the repair was not covered by warranty. Mostly reported between roughly 40,000 and 66,000 miles.

   2 related service bulletins

   What to check: Check coolant level and look for crusty residue or stains at the rear of the engine bay near the firewall; ask whether the coolant bypass valve or radiator has been replaced.

   2 excerpts from owner complaints in NHTSA records

   “I was idling in line for food when I noticed my thermostat gauge going slightly higher in temp. All of a sudden I hear a loud hissing sound and smoke coming off of the engine as well as a chemical burn smell. I pulled over to the side in fear that a fire could potentially start. After some research I’ve concluded that it is the rear coolant bypass joint. It was a high stress situation where my family was in my vehicle. Please look into this!”

   NHTSA complaint #11598095, filed 2024-07

   “Having two issues major issues that’s causing me a $10,000 bill. The timing cover is leaking and there is a coolant bypass hose that is leaking. I have spend a lot of maintenance on this truck on maintaining it to have to remove the engine. As for the forward collision warning ive had it go off multiple times witout a vehicle there. While in cruise control ive had it unexpectedly break on me when there was no visible vehicle infront or next to me.”

   NHTSA complaint #11755683, filed 2026-08
4. 4
   Brakes

   Brake pedal feels soft or goes to the floor

   • 7 complaints (9%)
   • median 5,300 mi at 0.9 yrs old (2 state mileage, few)
   • filed 2022–2026

   Owners describe the brake pedal sinking toward the floor, the truck creeping forward again after stopping at a light, and in one case a fluid leak onto the driver-side floor mat traced to the master cylinder. Complaints also mention rusted brake lines or assemblies and caliper or brake message warnings. Dealers variously replaced lines, pads and rotors or diagnosed a failed master cylinder or caliper. Reported from about 1,200 to 20,000 miles in most complaints, with some at higher mileage.

   What to check: Hold firm pressure on the brake pedal with the engine running and see whether it slowly sinks; check for fluid at the pedal, damp lines and heavy corrosion underneath.

   2 excerpts from owner complaints in NHTSA records

   “When stopping vehicle (for instance, at a stop light), vehicle would stop normally when pressing the brakes, but after a few seconds, the vehicle would start forward again. The brake pedal would give way and press down further, stopping briefly before starting forward again - so I had to use the emergency brake or else vehicle would move into oncoming traffic. I consulted a mechanic, and it was diagnosed as a bad brake master cylinder. This vehicle has only 51,000 miles on it, being a 2021 model. …”

   NHTSA complaint #11620230, filed 2024-10

   “truck is under 20 thousand miles right front brake shoes are loose and not in place. the whole brake assembly is completely rusted .brake lines are leaking.”

   NHTSA complaint #11700509, filed 2025-11

Buying note. Drive this truck at highway speed and in traffic before deciding, and check the brake pedal feel and coolant level; ask for records showing whether the coolant bypass valve, brake components or axle have already been serviced, and confirm any open service campaigns are completed.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.