# Toyota Prius coolant temperature warning light: complaints, recalls and what to do **Verdict:** Stop driving - **Owner complaints:** 22 - **Most complaints:** 2016 (10) - **Related recalls:** 1 - **Verdict:** Stop now ## Quick answer NHTSA has 22 owner complaints about the coolant temperature warning light on the Toyota Prius (2015-2026 models), most for the **2016** model year (10). There is **1 recall** for related parts; check yours by VIN. Stop driving: No. ## Toyota Prius coolant temperature warning light complaints by model year | Model year | Complaints mentioning the coolant temperature light | All complaints that year | Share | | --- | --- | --- | --- | | 2015 | 1 | 166 | 1% | | 2016 | 10 | 181 | 6% | | 2017 | 2 | 145 | 1% | | 2018 | 3 | 52 | 6% | | 2019 | 4 | 39 | 10% | | 2022 | 1 | 32 | 3% | | 2023 | 1 | 27 | 4% | Counts are complaints filed with NHTSA whose description mentions this light. They show where owners have had trouble, not a failure rate: popular years collect more complaints simply because more cars are on the road. ## Toyota Prius recalls related to the coolant temperature warning light **[21V734000](https://www.nhtsa.gov/recalls?nhtsaId=21V734000)** (2022 models, reported 2021-09-22): A loss of drive power increases the risk of a crash. **Remedy:** Dealers will update the ECU software, free of charge. Owner notification letters were mailed November 18, 2021. Recall repairs are free at any Toyota dealer. Enter your 17-character VIN at [nhtsa.gov/recalls](https://www.nhtsa.gov/recalls) to see whether yours is still open. ## What Toyota Prius owners report - "Passengers will overheat in the summer with no relief and I have no idea how this even made it on the market without vents to seats." -- owner of a 2023 Toyota Prius, complaint filed 2024 - "The catalytic converter appears to be overheating, causing the insulated sheathing in the hood to catch fire and/or melt. I discovered the defect this morning when I opened the hood to refill the windshield wiper fluid." -- owner of a 2022 Toyota Prius, complaint filed 2022 - "A few weeks ago, at around 10pm, when I was driving on the freeway, my car's engine temperature warning light suddenly on. The next day, I immediately sent my car to the dealer for a check up, the report stated '' coolant reservoir very low. Pressure tested system found exhaust center pipe leaking coolant..." -- owner of a 2019 Toyota Prius, complaint filed 2023 Excerpts from complaints filed with NHTSA, lightly cleaned for reading. They are owners' own accounts and have not been verified. ## What the coolant temperature warning light means A red coolant temperature light means the engine is overheating or about to. The most common cause is low coolant from a leak, followed by a stuck thermostat, a failed radiator fan, and a worn water pump. Pull over and shut the engine off as soon as it is safe, because continued driving can warp the cylinder head and destroy the engine. The most common causes, on any make: 1. **Low coolant from a leak** (most common) 2. **Thermostat stuck closed** (common) 3. **Radiator fan not working** (common) 4. **Failing water pump or broken belt** (less common) Full causes, what to do and how to reset it: [Coolant temperature warning light](/warning-lights/coolant-temperature). ## Frequently asked questions ### Is there a recall for the Toyota Prius coolant temperature light? Yes. NHTSA lists 1 related recall (21V734000) covering 2022 models. Recall repairs are free; check your VIN at nhtsa.gov/recalls to see if yours is open. ### Which Toyota Prius years have the most coolant temperature light complaints? In NHTSA's database the 2016, 2018 and 2019 Prius model years have the most complaints mentioning the coolant temperature warning light, with 10 for 2016. Complaint counts reflect how many cars were sold as well as how often problems happen. ### Is it safe to drive a Toyota Prius with the coolant temperature light on? Stop driving. No. Stop driving as soon as it is safe and shut the engine off. Driving an overheating engine even a few miles can cause damage that costs thousands of dollars to repair. ### How do I check if my Toyota Prius has an open recall? Enter the 17-character VIN from your dashboard or registration at nhtsa.gov/recalls, or ask any Toyota dealer. Open recalls are fixed free of charge, even if you are not the first owner. ## Sources - [NHTSA: Vehicle safety complaints and recalls (api.nhtsa.gov)](https://www.nhtsa.gov/nhtsa-datasets-and-apis) - [NHTSA: Check for recalls by VIN](https://www.nhtsa.gov/recalls) ## Other Toyota Prius warning lights - [ABS warning light](https://diagxcar.com/warning-lights/abs/toyota-prius): 40 complaints - [Airbag (SRS) warning light](https://diagxcar.com/warning-lights/airbag/toyota-prius): 4 complaints - [Brake warning light](https://diagxcar.com/warning-lights/brake/toyota-prius): 47 complaints - [Check engine light](https://diagxcar.com/warning-lights/check-engine/toyota-prius): 19 complaints - [Traction control light](https://diagxcar.com/warning-lights/traction-control/toyota-prius): 24 complaints ## Coolant temperature warning light on other models - [Ford Escape](https://diagxcar.com/warning-lights/coolant-temperature/ford-escape): 1520 complaints - [Ford Edge](https://diagxcar.com/warning-lights/coolant-temperature/ford-edge): 752 complaints - [Ford Explorer](https://diagxcar.com/warning-lights/coolant-temperature/ford-explorer): 222 complaints - [Honda Accord](https://diagxcar.com/warning-lights/coolant-temperature/honda-accord): 193 complaints - [Jeep Wrangler](https://diagxcar.com/warning-lights/coolant-temperature/jeep-wrangler): 143 complaints - [Nissan Rogue](https://diagxcar.com/warning-lights/coolant-temperature/nissan-rogue): 140 complaints - [Chrysler Pacifica](https://diagxcar.com/warning-lights/coolant-temperature/chrysler-pacifica): 139 complaints - [Kia Sorento](https://diagxcar.com/warning-lights/coolant-temperature/kia-sorento): 138 complaints - [Jeep Compass](https://diagxcar.com/warning-lights/coolant-temperature/jeep-compass): 112 complaints - [Kia Soul](https://diagxcar.com/warning-lights/coolant-temperature/kia-soul): 110 complaints ## Toyota Prius - [Toyota Prius specs and mpg by year](https://diagxcar.com/vehicles/toyota-prius) --- Source page: https://diagxcar.com/warning-lights/coolant-temperature/toyota-prius Updated: 2026-11-04 General information, not a substitute for a qualified mechanic.