Review on Enhanced Autel AL539B OBD2 Scanner: 3-in-1 Code Reader, Battery Tester, Avometer for 12 Volts Batteries, Advanced OBDII Diagnosis and Circuit Starting & Charging Systems Test by James Hova

I've done quite a bit of diagnostic work in the past and have used several different technical level diagnostic tools and automotive oscilloscopes - Snap On MT2500 (ex (e.g. Red Brick), Vantage, some OTC systems, GM Tech 1 and 2 and some engine analyzers from Sun and Snap-On. Let's get one thing straight: the AL539b is not a replacement for any of them. At $89 it shouldn't be, and that's fine. This is a code reader/scan tool that can perform several other diagnostic functions. It doesn't do anything fancy, but it's enough to sit next to my Launch X431. It's about something. As a scan tool, it falls somewhere between a typical entry-level tool (like an ELM327 dongle and a Torque smartphone app) and a high-end device. It does not perform bi-directional control, but it does read and clear codes, view and display real-time data, check I/M readiness monitor status, retrieve freeze frame data, etc. Many functions. Then there is the battery test function. By attaching a pair of alligator clips (supplied) to the unit you can test batteries, starters and charging systems. I've only tested a handful of batteries so far, but it's a useful feature, especially in a tool you'll likely have on hand when diagnosing a non-startup. My favorite part about this thing is that it has a built in scope (sort of). It has a multimeter that measures voltage, current, resistance, continuity, and performs a diode test. The readings are big and clear, which is nice. There is also an "oscilloscope" function that measures AC voltage or current. It's not a true oscilloscope - it doesn't have trigger options or a user-adjustable timebase - but it does give a visual readout of voltage or current, which is great for something like a crankshaft variable resistor sensor, or TPS. In variable voltage mode you also get maximum and minimum voltage, frequency and duty cycle. That's a lot of features for a sub-$90 tool. Defects? Well, the peak voltage that the meter/oscilloscope can measure is around 30V. It might not matter much, but don't confuse it with the Fluke 87 or you'll turn it into dross. The oscilloscope is designed for quick diagnostics and cannot set up a real oscilloscope (or even something like Vantage). The scan tool doesn't do bidirectional testing, but at this price point I'd be surprised if ANYTHING out there could. It can sometimes be a bit difficult to find the modules, especially on very early OBDII devices, and some of the error codes can be a bit generic. However, none of these things came close to breaking the deal. That's a lot of tool for the price. It will not replace a real scanner or oscilloscope, but will allow the knowledgeable home gamer or beginner to add many diagnostic options for little money. It's also a great grab and go tool for advanced users who need something fast and portable. no launch. In just a few minutes I can check the battery, charging system and scan codes. Excellent value for money if you only need basic diagnostics. UPDATE 12-2020: I've just discovered that this meter can't measure resistance (I've never tried it to date - get it). The meter feature has a continuity test that beeps but indicates an open circuit above 50 ohms. That's a shame, because now I have to take a separate multimeter with me, for example to measure the coolant temperature sensor. This makes it a little less attractive as a handy quick diagnostic tool. I'm not deducting a star - even without an ohmmeter, the thing is a solid bargain - but it would be very, VERY nice if you could at least measure resistances in the kOhm range. UPDATE 4-2021: I've used this on a car to monitor short and long term fuel settings while checking for vacuum leaks. The cord was barely long enough to allow me to hold the unit under the hood while pinching and poking around the vacuum lines. What I did was use a male to female DB15 cable to extend the cable that came with the AL539b. I ordered a 6ft cable from Revain for less than $7 and received it the next day. Another 6ft cable provides some flexibility for real-time data monitoring under the hood of a car. By the way, I still find myself saying that for a quick diagnosis this is more than my Launch X431. Launch has a lot more features (it's better 10x more expensive), but this Autel is quick and easy to use for basic codes and data. It's small, charges fast, rivals every vehicle I've tried so far, is probably more durable than a tablet, and the display is nice and bright.