Short answer: It uses automatic transmission fluid (ATF) that meets Dexron II or Dexron III specifications for its hydraulic power steering system.
The 2003 Toyota Highlander relies on a traditional hydraulic power steering setup powered by the engine. The fluid used in this system is not a separate, dedicated “PSF” product in most markets; instead, Toyota typically specifies ATF that conforms to Dexron II or Dexron III standards. Always verify the exact specification for your vehicle from the owner’s manual or the reservoir cap label, as regional differences can exist.
Fluid compatibility and guidance
Before listing acceptable fluid types, this guidance helps you understand what to look for and avoid when topping off or replacing the fluid:
- ATF that meets Dexron II or Dexron III specification (common choices for this era Highlander).
- Newer Dexron variants (such as Dexron VI) may be compatible in some cases, but confirm with your manual or a Toyota technician for your VIN.
- Avoid using non-ATF fluids (engine oil, brake fluid, or generic power steering fluids not labeled for ATF compatibility).
Concluding note: Using the correct ATF specification helps maintain steering performance and protect the pump. If in doubt, reference the owner's manual or consult a Toyota dealer to confirm the exact requirement for your vehicle’s production year and market.
How to check and replace the fluid
When you’re topping off or changing the power steering fluid, follow these practical steps to ensure proper maintenance without introducing air or leaks:
- Consult the owner's manual or the reservoir cap to confirm the exact fluid specification (Dexron II/III compatibility is typical for this model).
- Purchase ATF that meets Dexron II/III (or the recommended specification for your VIN) and have it ready.
- With the engine off, locate the power steering reservoir, remove the cap, and inspect the current fluid level and color. Clean any spills before resealing.
- If topping off, add ATF gradually until the level sits within the recommended range on the dipstick or markings. Do not overfill.
- Start the engine and turn the steering wheel from lock to lock several times to help bleed air from the system, then recheck the level and top off as needed.
- Check for leaks around the pump, hoses, and reservoir. Address any signs of trouble before driving.
Bottom line: For a 2003 Highlander, use ATF that meets Dexron II/III specifications, and consult your manual or a Toyota technician if you’re unsure about Dexron VI or market-specific recommendations.
Summary
The 2003 Toyota Highlander’s power steering system typically requires automatic transmission fluid that meets Dexron II or Dexron III specifications. When servicing, verify the exact specification on the owner’s manual or reservoir cap, and consider Dexron VI only if your manual confirms compatibility. Always use the correct ATF and follow proper bleeding and leakage checks to maintain steering performance.