Technical information

5
New Glow Plug Bore Reamer Available
New Tool Helps Diagnose CAN Bus Faults –
continued from page 4
The biggest difference between Message Monitor and
Detected State is that it passively monitors the bus, while
Detected State actively queries the bus. Actively querying
ECUs will make some of them stay awake. Obviously, keep
-
ing ECUs awake would be a bad thing if you're trying to
diagnose a power
moding fault.
This tab will tell
you which ECUs
have communi
-
cated in the past
1.5 seconds, how
long it's been
since ECU last
communicated
(if more than
1.5 seconds have elapsed), and how many times the ECU
was the first ECU talking on the bus (the bus is considered
'asleep' after 30 seconds of idle time).
Audible Feedback
The application can be configured in the Settings function to
beep when either a fault is detected or when the bus appears
electrically OK. Different beep strategies can be used in differ
-
ent scenarios.
In the case of a vehicle with a suspected intermittent bus
fault, you might want to make the application beep on faults
so that it will beep when the fault is detected.
In the case of a vehicle with a continually faulted bus, you
might want to make the application beep when the detected
fault goes away.
The application reacts to bus changes quickly (approximate
-
ly 100 ms). Wiggle connectors and listen for a beep.
Tracking Intermittent Faults
The application tracks the longest time it takes for each
control module to respond to a request. Control modules
which take longer to respond than their peers were/are likely
on the faulted side of the bus.
If the application is started on a faulted bus and a module
responds midway through the test, it will appear with a
non-zero time value in this field.
This number will not reset unless the reset (eraser) button
is clicked or the bus being tested is changed.
More Information
A user guide for the software is available in the GM Service
Information.
If you have any questions about the Data Bus Diagnostic
Tool, contact ACDelco Aftermarket Technical Support at
1-888-212-8959, prompt #2.
– Thanks to Chris Henley, David Gumpert, Bob Stewart and
Jill Laubach
Glow plug installation may
become difficult if carbon builds
up in the bore, which can reduce
the size of the bore and potentially
damage the tip of a new glow
plug. To address this condition,
a new Glow Plug Bore Reamer
(EN-51249) was recently released.
It’s now available for 2001-2010
Chevrolet Kodiak; 2001-2009 GMC
TopKick; and 2001-2015 Chevrolet
Express, Chevrolet Silverado
2500/3500, GMC Savana, and
GMC Sierra 2500/3500 models
equipped with a 6.6L Duramax
®
diesel engine (RPOs LB7, LLY,
LMM, LGH or LML).
Carbon may build up around
the glow plug tip during normal
engine operation. When it’s time
to replace the glow plugs, this buildup can make it difficult to
correctly install a new glow plug and may result in damage to
the new plug.
The Glow Plug Bore Reamer can be used to remove the
carbon. It is non-threaded so that it can work on multiple
model years.
When using the
tool, first apply a
light coat of wheel
bearing grease to
the inside of the
flutes. The grease
will retain the
removed carbon
and help keep any
debris from falling
into the engine.
Remove the ream
-
er occasionally to
clean any carbon
from the flutes and
re-apply the grease.
With the reamer
in the glow plug
bore, turn it by
hand with a ratchet while applying slight pressure in the bore.
The reamer’s hex drive will be at the same height as the hex
drive of a fully installed glow plug when the bore is complete
-
ly cleaned.
To order the Glow Plug Bore Reamer, call
1-800-GM-TOOLS.
– Thanks to Bob Malone and Rob Oulton
Glow Plug Bore Reamer
(EN-51249)
The reamer is
the same height as
an installed glow
plug.
Apply grease to
the inside of the
flutes to retain the
carbon.
Message Monitor passively
monitors the bus.