October 2022 - 30

TOOL BRIEFING
* AUTEL ULTRA SCAN TOOL
* IDENTIFIX
* SNAP-ON ZEUS OSCILLOSCOPE
* MITCHELL 1
* SNAP-ON VANTAGE LEGEND
COMPONENT TEST METER
* BLUE POINT EECTBOB
BREAK-OUT BOX
* FLUKE 233 DIGITAL
MULTIMETER
* POWER PROBE 3
CIRCUIT TESTER
This will help you to determine if you have
a single module down, or if the entire bus
is down.
Part of a diagnosis may be disconnecting
modules from the network bus to determine
if that module failed. We always start
with the most easily accessed modules or
bus bars. Some of the diagnostic may also
include checking the network at the module
connector with an oscilloscope such as
Snap-on's Zeus scanner (Figure 3).
We are looking to see if signal activity is
present and at the appropriate voltage levels.
We will refer to vehicle service information,
such as Mitchell 1 for specific network
voltage levels, and in some case instances,
" known good " waveforms.
Keep in mind that when we are looking
at network communication, the speed at
which communication occurs will not be
able to be seen by a voltmeter. It simply
doesn't have a fast enough sample rate.
Also, remember that most voltmeters are
average responding, which could be quite
confusing if you don't consider that. On
slower networks, you can use Snap-on's
Vantage Legend (a 2-channel power graphing
meter) (see Figure 4).
If you don't have access to an oscilloscope,
consider purchasing a logic probe.
Be careful to get one fast enough for the
network that you are working on. Knowing
the network speed and the speed your
tool is capable of are key to a successful
diagnosis. We are on the verge of going to
p Figure 3- A screenshot from a Snap-on Zeus scanner/oscilloscope showing CAN bus
network waveforms.
10Gps automotive networks with 5G and
" connected-cars " just around the corner.
SEEING IS BELIEVING
One of my favorite new tools for working
on networks is the Blue-Point EECTBOB
(an intelligent OBD-II breakout box)
(Figure 5). The tool is a great provider
of quick network status. It will show the
system voltages and grounds. You can
change the pin that you are looking at to
see voltage levels, and it also has LEDs
for each of the pins to visibly indicate
activity. Most of your vehicles today will
have multiple network protocols in use
at any given time. Because of this, you
must have the network topology map to
determine which network the problem
30 PTEN OCTOBER 2022 www.VehicleServicePros.com
exists in, and how to go about diagnosing
the problem.
In the example of a 2013 BMW X5, referencing
Figure 1, we used the Autel Ultra to
scan the vehicle. We were able to determine
we had a problem with the flex ray network.
We have trouble codes for no communication
with electronic power steering, and we
also have a trouble code for being unable to
communicate with the PCM (DME). There
were several codes in other modules for the
flex ray network being down as well, so that
raises a few questions:
1. Why did we get the trouble code from the
PCM for being unable to communicate?
The reason for this is that the PCM
also communicates on PT CAN and
PT CAN 2 buses.
p Figure 2- Identifix screen showing the factory wiring diagram for the Flex Ray network
from a 2013 BMW X5.
Diagnosis on the FlexRay
FlexRay is a new bus system and communication system. FlexRay ensures reliable and powerful data interchange between the
electrical and mechatronic components in real time. FlexRay serves for networking innovative functions of today and of the future
in the vehicle. FlexRay contains a powerful protocol for real-time-capable data transfer to different systems which are used in the
vehicle. With a maximum data transfer rate of 10 Mb per channel, FlexRay is very fast. It is significantly faster than the data buses
used to date in motor vehicles in the area of body, drive and chassis. FlexRay supports not only the higher bandwidth but also
deterministic data interchange; its configuration is error-tolerant. This means that even after failure of individual components, reliable
continued operation of the remaining communication systems is enabled. The central gateway module (ZGM) sets up the link between
the various bus systems and FlexRay.

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October 2022

Table of Contents for the Digital Edition of October 2022