Professional Distributor - 44

DIAGNOSTIC TECH
the idle air control valve (IAC valve)
used the same connector and were in
the same proximity. Sure enough, the
connectors were swapped. I restored
the connections properly and unfortunately, the elevated engine speed
continued. With the TP idle contacts
closed, I knew that a dead short on
a motor control circuit wasn't going
to be good for the circuit tasked with
its operation.
Since I wasn't too keen on having
to buy a replacement module, I took
it apart and found the two drivers for
the IAC valve with one clearly blown
up. I took the numbers off the transistor and found a replacement at a
local Radio Shack and soldered it in
place. After firing the engine back
up, the idle control system operation
was normal.

INDUSTRY OUTREACH
I reached out to one of my colleagues,
Matt Fanslow, the lead technician at
Riverside Automotive in Redwing,
Minnesota, to talk to about his experience with internal, board-level module
service. I asked him for a couple of
examples where he ended up making a board level repair rather than
replacing the module. Fanslow also
explained the reasoning for repair
over replacement.
"We recently had a vehicle come in
with a dead misfire. Within 20 to 30
minutes, we had the issue diagnosed
as a bad ignition coil driver within
the ECM," Fanslow says. "When we
checked with the OEM, we found that
this module was no longer available.
However, we were able to locate a
replacement unit (remanufactured) but
that would take a few days to arrive,
and with the high cost of the module
I immediately figured out how much
it would take to fix the module.
"Given the age of the vehicle and
the consumer's financial position,
we decided to take the board level
repair path. With the ECM pin out

diagram in-hand, and after pulling the
covers off the ECM, we were able to
identify the location of the defective,
surface-mounted transistor. With a
magnifier, I was able to pull identifier numbers from the chip and head
over to mouser.com and enter research
mode. What I found was that the part
I needed was readily available and very
inexpensive. Now, since I have been
performing similar board type of work
for a few years now, I had all the tools
available which would help me handle
this task quite efficiently."
Fanslow says several of his colleagues began repairing GM clusters
found on late 90's and early 2000
model year vehicles. He took their
lead and began offering that service
in-house, by reflowing solder joints
and/or replacing the stepper motors.
"At that time, I found that all I
really needed to get this job done was
a couple of soldering irons and a solder sucker," Fanslow says. "Most of
these tools I acquired inexpensively
at Radio Shack. Today, my arsenal of
tools that make up my rework station
have grown through necessity and
discovery, through discussions I've
participated in with fellow colleagues."
Fanslow says he sources his tools
from sites with replacement electronic
components. "Mouser (mouser.com)
and Digi-Key (digikey.com) will usually have anything you need," he says.
Jorge Menchu with Automotive
Electronics Services (AESwave) says
when it comes to board level repair,
developing electronics repair skills is a
personal investment and will separate
a technician from others in the field.
"Please be aware, you don't need to
be an electronics expert if you know
how to be resourceful and perform the
research," Menchu says. "There is a
tremendous amount of knowledge and
information, both good and bad, available on the internet. It's very possible
that you may be able find a solution
through someone else's experience."

44 Professional Distributor I August 2020 I VehicleServicePros.com

Menchu was working with a
Fresno City College auto instructor who had a student with an older
turbocharged Chrysler vehicle. The
vehicle had an intermittent misfire
he was trying to resolve. Through
research, the student discovered
through an enthusiast's forum that
the ECM in his vehicle likely has a
bad capacitor causing the symptoms he
was experiencing.
"The information he found contained very detailed guidance, including images that proved to be very helpful," Menchu says. "Since the student
was hesitant to take on the work, we
went ahead and installed the capacitor
for him. After the capacitor replacement, the symptom disappeared."
Menchu points out the student's
decision to not dive in and do the
job himself was a good decision for
two reasons: A likely beginner mistake would be to not notice that an
electrolytic cap is polarity sensitive.
Also, for those who have not worked
on an electronics board before, they
should pick up an old PCM and use
it for practice in order to hone their
soldering and de-soldering skills.

PROGRAMMING
It's no secret that many modules
today are reprogrammable, and oftentimes repairs ultimately come down
to updating a module's firmware or
calibration level. Reprogramming
might be something that seems challenging, but if you dig a little deeper,
you'll likely find that it's not all that
difficult to do.
Most manufacturers today offer
module calibration operations for
ECM's, TCM's, and more via J2534.
The J2534 standard came about as a
result of the Clean Air Act and OBDII. Many individuals and companies
dedicated a lot of time and effort into
developing this standard. The basic
premise is that after one acquires
a compliant J2534 interface and a

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