Skip to Content
Main Content

Ignition Current and Voltage Comparison

Having a hard time determining if an ignition coil is faulty? A quick test on your Snap-on diagnostic tool lets you compare the voltage and current of a coil to find a problem.

A two-channel test will allow you to view the primary voltage and primary current from the coil on the screen of your Snap-on car diagnostic tool - let's use the new Intelligent Diagnostics live on ZEUS system - meaning you can see if there is an issue.

With the coil set up, hook channel one up to the voltage element and channel two to the low amp current probe, set your ZEUS to record the data then turn on the vehicle’s engine and allow it to run for a few seconds so that the data can be captured.

After you have then paused the recording and turned the vehicle off, you can return to the screen and examine the findings.

The two readings should pretty much match up as voltage and current are so closely related and if they do, you know that the coil is good. If they don’t, further investigation is required.

** Although ZEUS has been used here to illustrate the procedure, it can also be operated on the MODIS Edge, MODIS Ultra, Vantage PRO™, Vantage Ultra™, VERDICT™, VERUS Pro and VERUS™ Edge scan tools. **