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TROUBLESHOOTING
ENGINE SYMPTOM DIAGNOSIS
[200 EA]
The Vehicle Management and Control
(V-MAC IV) system monitors engine function and
displays a code when a fault is detected. The
code can be observed on the instrument panel or
through an electronic diagnostic tool. An
explanation of the fault codes can be found in
VCADS, Guided Diagnostics or the Fault Code
Manual, 8-218. Guided Diagnostics also includes
symptom-based troubleshooting. To obtain Tech
Tool, contact your local MACK dealer.
The Tech Tool provides complete system
diagnostics. For more information, see manual
8-371 or the Tech Tool web site. Repair
information is available in the respective engine
service manuals and from the MACK Electronic
Information System (EIS). EIS is easily accessed
w it h Te c h To o l.
Troubleshooting Technique
Talk to the vehicle operator. Learn how the engine
operated before it failed. Ask about the
maintenance schedule and the fuel, coolant and
lubricant used. Begin by attempting to determine
whether anything has happened recently that
could point to the electrical system, but which is
not related to the electronic control system.
Depending on the vehicle configuration, a
problem may be caused, or influenced, by
malfunctions in other vehicle components. Be
sure to inspect for unusual conditions among the
batteries, tires, axles, trailer, bodybuilder
adaptations and other possibilities. Consult
specific service information resources according
to the conditions observed. Fuel waxing, for
example, can cause symptoms easily mistaken
for other engine problems.
If possible, recreate the problem in an
environment similar to that described by the
vehicle operator. Run the engine at the
temperature at which the symptom occurred.
Engine problems can be electrical, mechanical or
a combination of the two. Electrical and electronic
problems will, for the most part, cause fault codes
to be set in the V-MAC system.
Before Troubleshooting Begins
Before troubleshooting begins, observe all shop
safety procedures.
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