Klein MM720 TRMS Digital Multimeter with LoZ Mode

Most of the electrical work on a modern automatic is solenoid resistance, sensor voltage, and finding the break in a harness, and a cheap 2000-count meter will lie to you on all three. The MM720 is auto-ranging true-RMS, so a shift solenoid reading 20 to 30 ohms, a transmission fluid temperature sensor changing resistance as the pan warms, and a pressure switch going open or closed all read clean and settle fast instead of drifting.

The feature that earns its keep on a transmission job is LoZ. Probe an unplugged case connector with a normal high-impedance meter and the long runs of wire in a body harness will induce ghost voltage, so a dead circuit shows 4 or 6 volts and you chase a fault that is not there. LoZ mode drops the input impedance and bleeds that stray voltage off, so a dead wire reads dead and a live one reads live. That alone settles most "is the TCM even commanding this solenoid" arguments before you drop the pan.

It also does continuity, capacitance, frequency and duty cycle, diode test, and temperature with a thermocouple, so you can check a 0 to 100 percent PWM solenoid duty cycle off the same meter you just used for resistance. The display is a reverse-contrast LCD that stays readable under a lift, there are test lead holders on the back, and a kickstand so it will sit on the bellhousing while you probe. Rated CAT III 1000V and CAT IV 600V, which covers everything on a 12V or hybrid-adjacent vehicle you should be touching. Ships from the USA.