AUTOOL AS501 Digital Brake Fluid Tester - DOT 3/4/5/5.1 Compatibility, 1.8" HD Display, Stainless Steel Probe

The AUTOOL AS501 is a handheld digital tester that quickly measures water content in DOT brake fluids, delivering reliable moisture readings on a clear 1.8" HD screen.

Whether you maintain a personal vehicle or run a small garage, the AUTOOL AS501 takes the guesswork out of brake fluid checks. It senses conductivity changes caused by dissolved water and reports results fast, so you can decide when to flush or replace brake fluid without sending samples to a lab. The compact, battery-powered unit and corrosion-resistant probe make it convenient for roadside inspections, shop use, or routine maintenance.

How quickly does the AS501 give a brake fluid moisture result?

Results appear in about 10 seconds thanks to a sensitive sensor that detects changes in conductivity from moisture. The backlit 1.8" HD LCD displays readings clearly in sunlight or dim conditions, speeding inspections and reducing guesswork.

• Typical reading time: ~10 seconds
• Readable in low light: 1.8" backlit HD display
• Portable operation: 2 AA batteries provide long runtime

Which brake fluids and vehicles can it test?

The AS501 supports a wide range of brake fluids including DOT 3, DOT 4, DOT 5, DOT 5.1, ENV-4 and ENV-6, making it suitable for most cars, motorcycles and light trucks. This broad compatibility simplifies tool selection for mixed fleets and home mechanics working on different models.

• Supported standards: DOT 3/4/5/5.1 and ENV-4/ENV-6
• Suitable for: passenger cars, motorcycles, light trucks
• One tool for multiple fluid types—no swapping devices

What features ensure accurate and durable readings?

Accuracy comes from advanced detection technology that measures water-induced conductivity changes and reports moisture percentage. A stainless steel probe resists corrosion from brake fluid and is flexible for reaching reservoirs in cramped engine bays.

• Advanced boost detection for precise moisture measurement
• Stainless steel corrosion-resistant probe for longevity
• Consistent calibration built into the electronic sensor

How easy is it to use and maintain the tester?

Operation is straightforward: power on, insert the probe into the brake fluid, and read the value on the HD screen. The device runs on two AA batteries for low-cost replacement and is backed by a three-year support plan for parts and technical help.

• Simple one-person operation—no special training required
• Battery-powered: 2 AA batteries for convenient power
• 3-year service and technical support for long-term use

Who this is for: The AUTOOL AS501 is designed for DIY car owners, motorcycle enthusiasts, fleet managers, and independent mechanics who need a quick, portable way to assess brake fluid condition. If you want to spot moisture contamination early and make informed maintenance choices without lab tests, this tester offers a fast, user-friendly solution with broad fluid compatibility and durable construction.