32 | September/October 2014
ECU soft resets
Killing power to on-board modules does
wonders in diagnosis and repair
By Craig Truglia
Craig Truglia is an ASE A6 and A8 certifed
technician who presently works as a service
writer for Patterson Auto Body, a repair facil-
ity in Patterson, N.Y. A former shop owner
and editor of several automotive repair
magazines, Truglia combines his Columbia
University education with the real-world
experience he sees daily in the automotive
repair feld. Technicians Truglia, Fred Byron
and Cristian Cordova took part in diagnosing
the different vehicles in this article.
W
hen a smart phone is not working
quite right or a PC gets frozen,
what's the easiest way to fx it?
Turn it off, start it back up, and hope the
problem is gone. Some PC users even wait
a few seconds to turn the device back on,
hoping it gives time for the computer chips
to power down.
Without getting all scientifc about why
this works on computers, the principle is
simple. When a computer acts screwy, some-
times it needs to be reset so it can work
right (see Figure 1).
Connections
Figure 1: This 2011 Buick Lucerne had an issue with its transmission control module (TCM)
that was repaired with an engine control unit (ECU) soft reset.