MACS Service Reports - 2016 - APR4

Dave Hobbs

Dave Hobbs

SCAN TOOL SWISS CHEESE

Figure 8: This PID graph on a Ford CMAX Hybrid uses a high voltage
electric HVAC compressor. A CAN bus message from the HVAC controls
to the electric compressor controls cooling operation. A bi-directional
command could do the same. Since high voltage is involved, a 'jumper'
procedure is out of the question. Your tool's accuracy in sending the correct CAN message to the compressor will have to be spot on in order to
diagnose this newer technology.

Holes in coverage and holes in accuracy happen
frequently enough to be a major reason why many
higher end shops build plans into their tool budgets
for the purchase (and upkeep / update) of true factory OEM scan tools based on the shop's trends in
brand popularity and ROI (Return On Investment).
These holes were the topic of a training class put on
by mobile technician, writer and automotive trainer
John Anello (Auto Tech On Wheels) at a trade show
recently. As a humorous illustration, John produced
for the class of technicians a new aftermarket OE
level scan tool. The new tool was actually a project box with a DLC cable attached. Fastened to the
front was a large slice of Swiss cheese. He explained
to the technicians attending his class that the larger
holes of coverage and accuracy (once discovered)
in his scan tool were bound to be filled very soon
by the tool manufacturer. Some of the small holes
John noted may never get filled in, and he would
know - looking at a scan tool count on his mobile
tech website www.autotechonwheels.com he currently
has two general all makes / all models "OE Level"
scan tools (Modis Ultra and Autel MaxiSys Mini)
and two very OEM dedicated OE Level scan tools
(Ross-Tech VAG-COM for VW/Audi and the highly
coveted Autologic European specialized OE Level
tool with software suites for at least six Euro name
plates). For speed in highly advanced, specialized
drivability, the ATS generic OBD-II PC based EScan, known for its fast engine VE and catalyst ef-

April 2016

4

mobiletechonwheels.com

Figure 9: This Toyota Sienna's optional scan tool enabled A/C customization menu is the crème-de-la-crème of advanced functions for any scan
tool.

Figure 10: If you want to really get the most out of scan data you need
to have a collection of scan tools - not just one or two. Put together an
intelligent plan based on: 1.) How many of a particular OEM you service
per month; 2.) How many times your current "OE Level" scan tool has
holes of coverage and accuracy on a particular OEM / model of vehicle;
3.) Update costs vs. replacement costs.

ficiency testing, fuel trim trend graphing analysis
and ultra user friendly Mode $06. As for true dealer
OEM factory scan tools? According to his website,
he owns 17 of those tools!
Scan tools of the non-factory / OEM dealer variety have always been hit and miss with bi-directional controls. While we do see the occasional unbelievable PID values on the OE Level scan tools we
frequently use, there are a few occurrences where
we see something that raises an eyebrow. You may
have seen something strange and asked yourself,
"Hey, how can the A/C high pressure be 0 PSI while
this car is blowing out such cold air?" On rare occasions the tool will show a PID that is totally out of
place. Values of glow plug current on gas engines

MACS Service Reports
http://www.mobiletechnzwheels.com http://www.autotechonwheels.com
Table of Contents for the Digital Edition of MACS Service Reports - 2016
