MACS Service Reports - 2015 - MAY7

COLORADO/CANYON BLOWER

The Chevy Colorado and GMC Canyon are GM's
new "mid-size" pickups. There has been a line of
these vehicles for some years, but to promote the
sales of smaller pickups for greater fuel economy,
these trucks were completely redesigned. That old
4.2-liter in-line six, 3.7-liter in-line five, 2.9-liter
in-line four and even the 5.3-liter V8 all are gone.
Today's engine choices are a 2.5-liter four-cylinder
and a 3.6-liter V6 (with variable valve timing and
direct fuel injection). So unless you're looking for
a tow service vehicle, this might be for you, at a
significantly lower cost than the full-size pickup,
whether a Silverado/GMC Sierra or Ford F-150.
What we want to point out is that these new pickups are on GM's new Global Architecture electrical
system. That means a lot of things, one of the most
important of which is that you can't swap control
modules. Global Architecture came in 2010 on the
Buick LaCrosse and Regal, Cadillac SRX, GMC Terrain and Chevy Equinox (crossovers) and Chevy
Camaro. It's not quite across the board on GM, but
it's getting there, and the Colorado and Canyon are
a couple of the new additions, and unsurprisingly
they have the second generation version (GDS 2).

As GM puts it, "When certain modules are programmed and configured during installation, those
modules learn a specific environment identifier that is
unique to the particular vehicle. If an incorrect immobilizer identifier or a specific number of incorrect environment identifiers are sent or received, vehicle starting is
disabled."
That means that a swap could tell the immobilizer identifier (anti-theft system) that something is
wrong and to not let the car start. Inasmuch as a
stolen vehicle may be involved in the module swap,
the immobilizer doesn't know it's a technician just
trying to diagnose a car problem, so it activates its
anti-theft strategy.
The Colorado/Canyon HVAC blower motor is a
brushless design that uses Back Electromagnetic
Field (EMF) to control operation. An electromagnetic field (EMF) is a physical field produced by
electrically charged objects. It affects the behavior
of charged objects in the vicinity of the field.
And now for a Colorado/Canyon blower motor
operating strategy you should know: on startup, it
goes through a phase that builds up with what may
seem like hesitation, but (from 20 to 450 rpm) it's
actually a mode in which enough current is generated to synchronize the rotor with the magnetic
field, and then the motor goes through a normal
ramp up.

Here's a list of do-not-swap
control modules:
*
*
*
*
*
*
*
*
*
*

Another "It's Normal"
As we've said a number of times before, you can
infuriate a customer with "It's normal," when he has
enough familiarity with the car and system to know
that "it" isn't. And as we've also said, you don't
usually get a complete description of the software
strategy to know when an "occurrence" is normal
and when it isn't.
Here's a normal mode on the 2011-on Ford F-150
blower (or movement of the recirculation door). All
of a sudden the blower motor may change speed and
the recirc door may move to increase the amount
of recirculated interior air. The driver is likely to
say, "I didn't touch anything, and suddenly this is
happening." The answer is that the climate control
software is intended to improve cabin warming in
cold weather or cooling in hot weather. There's no
bypass for this kind of strategy. ■

Engine (ECM)
Radio
Body (BCM)
Electronic Climate Control (HVAC)
Transmission (TCM)
Sensing and Diagnostic (SDM)
Electric Power Steering (EPS)
Hybrid Powertrain
Vehicle Communication Interface (VCI)
Instrument Panel Cluster (IPC)

May 2015

MACS Service Reports

Table of Contents for the Digital Edition of MACS Service Reports - 2015