Common Problems with the Lexus RX 450h
FixMyCar discusses common problems with the Lexus RX 450h and average repair costs.
Compare Lexus RX repair quotesEllie Dyer-Brown
Thursday January 15 2026
6 min read
The Lexus RX 450h is a hybrid luxury crossover SUV that replaced the earlier RX 400h.
This guide examines known issues with the RX 450h, providing owners and potential buyers with insights into specific faults and their average repair costs.
In a nutshell: The Lexus RX 450h has a strong reputation for reliability, and serious hybrid-system faults are rare. The most common issue owners report is the 12V battery going flat if the car isn’t used for a few weeks, while some models can also suffer power tailgate faults, aircon problems and occasional bodywork/trim niggles. Overall, it’s one of the best used buys in its class for reliability, especially with a full service history.
What’s wrong with the Lexus RX 450h?
Drivers are searching online for information about the following problems.
Lexus RX 450h battery drain problem
Some drivers report the battery of their RX 450h goes flat after two to three weeks of not being used, which is especially inconvenient in a hybrid car because the battery can’t be jump-started. Instead, it has to be trickle charged, or the circuits in the hybrid system will be damaged.
If the battery keeps draining despite frequent use, it may need to be replaced.
Average battery replacement price: £247.33
Lexus RX 450h hybrid problems
The good news is that the RX 450h’s main hybrid system (motor and high-voltage battery) has a very strong reliability record, and outright hybrid-drive failures are considered rare. The only issue to be aware of is the small 12-volt battery that powers the car’s electronics. As mentioned above, it can drain if the car isn’t used for a couple of weeks.
Recalls
| Recall number | Date | Reason |
|---|---|---|
| R/2020/060 | 05.10.20 | The low pressure fuel pump located in the fuel tank could become inoperative. |
Lexus RX 450h 2009-2016 problems
1. Flat 12V battery
Even though it’s a hybrid, the RX still relies on a small 12V battery to power the electronics. If it’s left unused for a while, it can go flat, leading to starting issues and warning messages.
What repair is needed for a flat 12V battery, and how much does it cost?
A garage will test the 12V battery and charging system, then recharge or replace the battery if it’s weak. The average price of a battery replacement on FixMyCar is £247.33.
2. Tailgate motor failure
Tailgate motor failures are a known RX issue (common on cars with powered boots), which can show up as the tailgate struggling, stopping partway, or refusing to open/close properly.
What repair is needed for tailgate motor failure, and how much does it cost?
The motor needs to be replaced, sometimes with the latch or struts. Typical costs are around £300-£900, depending on whether it’s a motor, latch, wiring, or strut-related fix.
3. Hybrid battery cooling faults
RX models of this generation can develop hybrid battery cooling faults, triggering warnings or reduced hybrid performance if the cooling system isn’t working properly.
What repair is needed for hybrid battery cooling faults, and how much does it cost?
Often a repair involves cleaning the battery cooling intake/fan (roughly £50-£150). If the fan itself has failed, replacement is more like £250-£600.
4. Air suspension leaks
Air suspension leaks are common in high-spec models (lower spec versions don't have air suspension). Symptoms include one corner sitting low, a bouncy ride, or the compressor running often.
Learn more about diagnosing suspension problems here.
What repair is needed for air suspension leaks, and how much does it cost?
The repair usually means replacing a leaking air strut/bag or the compressor. Costs are typically £800-£2,000+ depending on what’s failed and whether you use OEM parts.
Lexus RX 450h 2016-2022 problems
1. Air conditioning faults
Some owners report the aircon not blowing cold, cutting in and out, or taking ages to cool the cabin.
What repair is needed for air conditioning faults, and how much does it cost?
The first step is usually an air-con pressure/leak check and regas (around £70-£120). If there’s a leak or a failed part, common repairs include a condenser replacement (roughly £250-£600) or a compressor replacement (£424.27 on average).
2. Bodywork issues
Bodywork issues are common for this model, typically including things like loose trim, seals that don't work, or minor water ingress.
What repair is needed for bodywork issues, and how much does it cost?
The repair could involve securing trim, replacing clips, or adjusting/replacing a seal, often £50-£200. If water has soaked carpets and needs drying/removal, it can rise to £200-£500+.
3. Flat 12V battery
Like its predecessor, this generation of the RX 450h can suffer from 12V battery issues if it's not used much.
What repair is needed for a flat 12V battery, and how much does it cost?
A garage will test the 12V battery and charging system, then recharge or replace the battery if it’s weak. The average price of a battery replacement on FixMyCar is £247.33.
Lexus RX 450h+ 2023-present problems
Right now, there isn’t enough reliability data to confidently list problems with the 2023-present Lexus RX. Based on previous generations, the most frequent issues for cars under five years old are electrical/infotainment glitches and 12V hybrid battery issues.
Lexus RX 450h years to avoid
The RX 450h is consistently rated as a reliable used buy across both the 2009-2016 and 2016-2022 generations, so there aren’t any specific years that should be avoided. When buying used, take it for a proper test drive to make sure everything feels and works as it should, and ideally choose one with a full service history.
Find out what to look for when buying a used car.
Is the Lexus RX 450h reliable?
What Car?'s 2025 Reliability Survey saw the 2016-2022 RX named "most reliable luxury car", with an excellent rating of 97.9%, and the year before that, Lexus was named the second most reliable car brand.
Overall, that backs up the RX 450h’s reputation as one of the safest used buys in its class. Serious hybrid-system failures are rare, and most reported problems tend to be minor electrical or cabin-equipment issues rather than big mechanical bills. As always, you’ll still want a full service history and a proper test drive, but on the evidence, the RX is a strong choice if you’re prioritising long-term reliability.
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- Common Problems
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Ellie is FixMyCar's Content Manager. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers that is easy understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.