Lawmakers want to know more about Volkswagen's massive cheat — how the automaker used software to crank up the power on a vehicle, and then hide the fact.… ...

The nefarious workaround — and the crux of the Dieselgate scandal — was for engineers to reprogram the vehicle's Electronic Control Unit (ECU).

An entire marketplace exists on the Internet for tuners, devices that help drivers crank up the power on vehicles and then hide the evidence. We visit a local diesel shop to see how it works.

An entire marketplace exists on the Internet for tuners, devices that help drivers crank up the power on vehicles and then hide the evidence. We visit a local diesel shop to see how it works.