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 Chris Munns

This has saved me a lot of money on exhaust repairs. that's the main reason I got it. 1> It has an oscilloscope function on the multimeter. By the way, the multimeter is designed for only 30 volts, a maximum of 20 amperes, which is enough to work with almost any car. I used it to record the current amplitude of the fuel pump (the pump was fine) and the crankshaft position sensor (it was bad) 2> It has a built in battery capacity tester. The battery capacity tester costs the same as this device 3> It has live data you can set up for the sensors you want to view at the same time. I have used it to troubleshoot my engine (V8) that is running lean at idle. Both banks of O2 sensors were found to be running with a negative fuel trim (-12) meaning it was not a leaking injector (a leaking injector would indicate a correction in the relevant sensor bank where the there is a leaking injector). Found that the mass air flow meter is dirty. Cleaned with Mass Airflow Cleaner Spray. Now the fuel trim works at -1 < 0 < 1 at idle. I got lucky! 4> There is an Autel AL539 B YouTube channel by a fully independent mechanic. From time to time he shows off his Snap-On Vantage Pro scanner and compares it to this one to prove that this device is just as capable as the Snap-On but cheaper.