10 Common Problems Of A Lexus RX350

What kind of problems does a Lexus RX350 usually have? In this blog, we’ve outlined the most important things you should watch for when you’re in the market for a Lexus RX350. In the rest of the article, we’ll discuss every single problem in detail. Furthermore, we’ll tell you how to identify it, fix it and how much it costs to fix. Read on!

Common problems in Lexus RX350 from 2015 onwards are faulty rain sensors, rattling doors, the car abruptly braking by itself, and malfunctioning of the infotainment system. Models before 2015 have failing A/C units, rough idle and misfiring due to a dirty electronic throttle body, and significant oil leaks due to a broken VVT-i line.

However, that doesn’t tell the whole story. In the rest of the article, we’ll discuss every single problem in detail. Furthermore, we’ll let you know how to identify it, fix it, and how much it costs to fix it and ensure the longevity of your Lexus RX350. Read on!

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Exterior Issues

1. Faulty Rain Sensors

Electrical sensors have made the current automobile feature-rich with new features added and old features improved with each new model. One such feature is the rain-sensing windshield. The windshield has sensors built into it to sense the intensity of rain and adjust the wiper speed accordingly, thus giving drivers a better user experience.

However, 2016 – 2017 models of RX350 have had issues with these sensors, with some owners complaining of reduced efficiency at night. Another issue that has been reported has to do with the wiper malfunctioning even when the sensitivity dial is set to maximum. The only remedy for this problem is to replace the sensor, which costs about $350.

I have a 2017 RX 350 with one month left to go on the warranty. I took it to the dealer because the rain sensing windshield wipers are not working correctly. As it turns out the sensor has developed bubbles/an air pocket between itself and the windshield.

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Interior Issues

2. Air Condition Failure

Air conditioning is essential for a comfortable ride in the summer months. Unfortunately, HVAC issues are among the most common problems in vehicles. The most common air conditioning complaint is AC blowing hot air. It could be due to a faulty compressor or compressed gas leakage.

Lexus RX350 has a history of air conditioning problems, mainly affecting the 2007 – 2013 model years. This failure is due to a fault with the AC amplifier. An AC amplifier is the brain of the HVAC system. The inputs (temperature, pressure, etc.) come from the sensors and controls, and the outputs are used to control to engage the compressor, operate servos for vents, etc.

AC amplifier failure can lead to the air conditioning blowing hot air, or sometimes it will intermittently blow hot and cold air, or some vents would not blow any air at all. Replacing the amplifier yourself isn’t that hard, but expect to pay $500 – $700 for an OEM amplifier. Watch the video below to see what the replacement entails.

3. Airbag Warning Light with Fault Codes

The airbags in modern cars are a huge safety feature, along with the seatbelt harness. Airbags have been instrumental in saving countless lives; hence these must deploy when needed. Non-deployment of airbags can mean a difference between life and death.

In RX350, a sensor continuously monitors the supplemental restraint system, including the airbags and the seatbelts. In case of an issue, a warning indication is constantly lit, and fault codes are generated. Diagnosis of fault codes clarifies the exact nature of the problem. In the case of airbags, the fault codes B0111 and/or B0116 are generated.

Several service bulletins have been issued for the Lexus RX350 supplemental restraint system, and generally, the fault is removed with the replacement of several airbags. Exterior Issues.

4. Rattling Doors

Lexus is a high-end car manufacturer, and having owners complain of loose parts rattling can harm its reputation. But this is precisely what has happened with a couple of RX350 models. Owners have complained of rattling doors while driving on the freeway. Others have complained that their doors came loose, creating a safety hazard. We’ve heard these complaints with the 2008 – 2010 model years, but they’ve seemed to return in the 2019 – 2020 model years.

Tightening loose nuts and bolts, re-aligning doors, changing worn-out window regulators, masking tape between metal to metal contact, and changing window guides can alleviate the problem.

5. Vehicle Speed Control Malfunctions

This is one of the largest culprits in the 4th generation of the Lexus RX350 (from 2016 onwards). The problem is the vehicle speed control system, and it has been reported in many other Toyota and Lexus models. As the name suggests, this system controls the vehicle’s speed and ensures that it’s not going too fast or too slow in certain situations.

One recurring problem this car has is that the system malfunctions severely. This typically happens when the driver is trying to park the vehicle. Reports paint the same picture repeatedly: the driver is pulling into a parking spot, they push the brake pedal, and instead of stopping, the car accelerates rapidly, which results in a crash.

On other occasions, the exact opposite happens, and the car is driving on the highway and decides to brake itself rapidly, creating hazardous situations.

Interestingly, this problem is that Toyota (the owners of Lexus) has never admitted to their cars having this problem. However, the Lexus 300h, Camry Hybrid, Highlander Hybrid, and Avalon Hybrid also have this problem which means something has to be structurally wrong.

In the case of the Toyota Camry, the company even settled a few court cases regarding issues with the vehicle speed control. In these cases, lawyers argued that the electronic throttle-control system software was at fault. It’s likely the problem is similar for the RX350.

Engine Problems

6. Electronic Throttle Unit Issue

Modern cars have their accelerator pedal electronically connected to the throttle via the Electronic Throttle Unit (ETU); hence, no mechanical linkage is involved. ETU consists of an accelerator pedal module with multiple sensors, an electronic throttle body, and an engine control module.

The electronic throttle body is a critical element of the ETU, and its function is to control the amount of air let into the system based on how far the accelerator pedal is pressed. A bad throttle body can have one or more of the following consequences.

• Check Engine Light
• Rough idle.
• Rough acceleration.
• Misfiring during acceleration.
• High or low Idle RPM.
• Poor engine performance.

Model years 2007-2011 of RX350 are prone to electronic throttle body failure, generating a fault code P0505. If this happens, the remedy is replacing or cleaning the throttle body. The average RX350 throttle body replacement cost is $443, with $301 for parts and $142 for labor.

Therefore, it’s worth trying to clean the throttle body first. Below are instructions on how to do this (the video is for the RX450h, but it should be pretty similar).

7. Oil Leaks and Loss of Oil Pressure

Engine oil is of utmost importance in keeping the moving parts lubricated to prevent metal on metal from rubbing against each other. Engine oil gets in between the very minute spaces between moving parts, creating an atom-thin layer that thus prevents complete contact. Without engine oil, this metal-on-metal contact will destroy the engine very quickly.

Given the importance of the engine oil, it is essential to keep an eye on the engine oil level and its color and smell. The level should not drop below the minimum level marked on the dipstick, should not be very dark-colored, and should not smell burning. Any of these indications mean that the oil needs to be changed.

Given the pivotal role of engine oil, it is surprising that nine RX350 models (2007 – 2015) have been reported for major oil leaks. The leak is so massive that it covers the ground, the engine, and the undercarriage and leads to immediate loss of oil pressure, which means the car is no longer safe to drive. If it is driven, then most likely, the engine would seize.

The cause of the leak is the bursting of a VVT-i line, generating a “Low Engine Oil” message. Additionally, the engine oil pressure warning light will be lit. If the car is continued to be used, it will result in complete engine failure due to oil starvation.

It is a known problem, and Toyota has issued a revised part for it, but unfortunately, the fixed part has been reported to have the same issue. The estimated labor cost is between $88 and $111, while parts cost $145. After replacing the line, cleaning the engine bay and undercarriage is necessary.

Transmission Problems

The car transmission is responsible for delivering power from the engine to the wheels. The transmission converts the right amount of power to the right amount of speed. Transmission issues can result in poor car performance and an uncomfortable and jerky ride. Car transmission also decreases the fuel efficiency of your RX350.

The RX350 was first released in 2007, and ever since then, there have been some isolated reports about the transmission quality in several model years. However, there are no technical service bulletins or recalls, indicating that the problems aren’t that widespread.

Nevertheless, it’s essential to be mindful of this when you’re in the market for an RX350. Transmission problems include hard shifting, delayed shifting, burning smell, or car shaking or jerking at any speed. Ignoring issues with transmission can aggravate the problem, as can things like towing too much weight with your RX350. In the worst-case scenario, the car cannot be driven. Behind the engine, a well-maintained transmission ensures that the car will last a long time.

8. Delayed Shifting

Lexus RX350 owners complain of delayed shifting and hesitation when moving from the start. Delayed shifting is usually caused by valves sticking to the valve body. When this happens, the shifting does not take place when it should. Modern transmission is electronically controlled, so the problem could be with the shift solenoid that triggers shifting.

In some cases, servicing the transmission may solve the problem; otherwise, transmission replacement would be required, costing over $3500.

9. Faulty Variable Valve Timing System

Your car engine is a complex system with many individual pivotal parts that work in a synchronized manner to provide the necessary power to run your car. One such part is the camshaft, a cylindrical valve with several cams or lobes extending outwards from the camshaft at the specified location. Each cam is positioned in one of the engine’s intake and exhaust valves. Valves regulate the process of mixing fuel-air through the cylinders.

Camshaft ensures that control of closing and opening of each particular time at the precisely correct time synchronized with the movement of the piston in each cylinder and firing of each spark plug.

The camshaft is an essential piece in the engine jigsaw, and if it is in good shape, expect your car to respond appropriately. A poorly performing camshaft can impact the whole performance of your car. Some signs of a bad camshaft are:

• Misfiring cylinders at low or high RPMs
• Loud tapping noise coming from the valves.
• Backfiring and popping.

Lexus RX350 models, 2007, 2008, and 2010 are known to have issues with the Variable Valve Timing (VVT) system resulting in AWD, Traction Control, and Check Engine lights being lit. It also results in the generation of fault codes P0012 and P0014.

If there is an issue with VVT, the check engine light will be lit with error codes generated. A new oil control valve costs between $40 and $120 plus labor costs.

Electronics Issues

10. Issues with Infotainment System

All modern cars have an infotainment system, an innovative and efficient way of having entertainment and information accessible all in one place. You can listen to your favorite music and have information such as weather and traffic updates, driving directions, and much more. The infotainment system has become a key feature looked at by car buyers.

RX350 model years 2007, 2010, and 2014 have reported issues related to the Infotainment system. However, 2016 – 2019 owners have also reported the same problems. In particular, owners complain of issues with the radio, Bluetooth features, and navigation displays. It happens due to a software glitch, and updating to the newer software version solves the problem.

It occurred on my 2016 RX multiple times when brand new and they applied a software update and it stopped after. I was told that updates are received over the air and that sometimes the update does not happen correctly (for me due to the fact that I keep it inside a garage?). They had to flash it manually using a USB stick.

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Closing Thoughts

In wrapping up, we’ve provided a comprehensive overview of the key issues commonly associated with the Lexus RX350.

From models released before 2015 to those manufactured thereafter, owners and potential buyers should be well aware of challenges like malfunctioning rain sensors, A/C unit failures, and issues with the infotainment system.

If you’re on the market for a Lexus car you might want to consider checking our other articles showcasing issues with other models like the Lexus RX450h Hybrid, and many more.

By being informed, you can approach maintenance or purchase decisions with confidence. Remember, while these problems might seem daunting, many vehicles have their quirks. With timely and proper care, the Lexus RX350 can still serve as a reliable and enjoyable ride. Stay informed, stay safe, and happy driving!