Guide to the 2007-2009 Lexus RX350 Power Steering Pressure Switch
Solve engine stalling during turns by understanding this critical power steering sensor.
- The primary symptom of a bad switch is the engine stalling or stuttering during low-speed turns.
- Before replacing any part for a fluid leak, check for the common steering rack leak covered by TSB L-SB-0107-12.
- A quality aftermarket brand like Standard Ignition is a reliable and cost-effective choice for this repair.
- The repair is simple, requires basic tools, and is feasible for a DIY mechanic.
Symptoms of a Failing Power Steering Pressure Switch
When the power steering pressure switch fails, it sends incorrect information to the engine's computer. This can cause several noticeable problems, especially when turning the wheel.
- Engine Stalls or Stutters When Turning: The most common symptom is the engine RPM dropping or the engine stalling completely when you turn the steering wheel at low speeds, like in a parking lot. This happens because the computer doesn't know it needs to bump the idle to compensate for the power steering pump's load.
- Erratic Idle: Your RX350's idle might become unstable, speeding up and slowing down on its own as the computer tries to make sense of the faulty signals from the switch.
- Fluid Leaks: The switch itself has seals that can fail over time, causing a power steering fluid leak. A leak can lead to other symptoms like a whining noise from the power steering pump and increased steering effort due to low fluid.
- Check Engine Light: A malfunctioning switch can trigger the Check Engine Light on your dashboard.
Important: Check for Steering Rack Leaks First!
Before you replace the power steering pressure switch for a fluid leak, it is critical to inspect the entire system. The 2007-2009 Lexus RX350 is known for a common issue where the power steering rack and pinion assembly develops leaks from the steering gear boots. Lexus issued a Technical Service Bulletin (TSB L-SB-0107-12) for this exact problem. A leaking rack can cause fluid loss, leading to a noisy pump and hard steering, which can be misdiagnosed as a bad pump or switch. Always confirm the source of a leak before buying parts.
Choosing the Right Aftermarket Switch
For a part like this, you don't necessarily need to buy from the dealer. Reputable aftermarket brands offer a quality alternative at a good price. Here's a look at the brands available.
- Good Tier (Standard Ignition): Standard Motor Products (SMP), sold under the Standard Ignition brand, is a well-regarded aftermarket manufacturer. They state their switches are fully tested and use quality materials. For a simple sensor, this brand offers a reliable and cost-effective repair that should perform well.
- Economy Tier (Replacement, True Tech): Brands listed as "Replacement" or "True Tech" are typically entry-level, budget-focused parts. While functional, their long-term durability and quality control may not match that of more established brands like Standard Ignition. Given the low cost of the part and the minimal labor involved, they can be a viable option if budget is the primary concern.
Pro Tip: When replacing the switch, it's a good idea to also get a small amount of the correct power steering fluid. Your RX350 uses DEXRON II or III type Automatic Transmission Fluid (ATF), not generic power steering fluid. You will lose a small amount of fluid during the swap.
Cost of Replacing the Power Steering Pressure Switch
| Part Type | Price Range |
|---|---|
| New Aftermarket | $32.66 - $67.43 |
| New OEM | $50 - $70 |
| Shop Labor | $75 - $150 |
Frequently Asked Questions
Where is the power steering pressure switch located on a 2007-2009 RX350?
The switch is located on the high-pressure line, typically screwed directly into the body of the power steering pump. You will need to remove the engine cover to see it.
Can I drive my Lexus with a bad power steering pressure switch?
Yes, but it's not recommended for long. While the car is drivable, the risk of the engine stalling during a low-speed turn, such as pulling into traffic, poses a significant safety hazard. It's best to get it repaired soon.
Will a bad pressure switch make my steering hard?
Not directly. The switch is an electronic sensor. However, if the switch itself is leaking power steering fluid, the resulting fluid loss will cause the pump to whine and the steering to become stiff.
Is replacing the power steering pressure switch a DIY job?
Yes, for most home mechanics. The job involves unplugging the electrical connector, unscrewing the old switch, and quickly installing the new one to minimize fluid loss. You will need basic hand tools and may need to top off the power steering fluid afterward.
Technical Specifications
OEM Part Numbers: 89438-33010
The 2007-2009 Lexus RX350 uses a hydraulic power steering system that requires DEXRON II or III type ATF fluid.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Lexus RX350: