Spicer TPCS Troubleshooting Guide - Manual (Page 19)

16
Diagnostics
Tr
oubleshooting T
ips
Troubleshooting Tips
This checklist outlines some general hints and guidelines that
will be helpful in tracking down and correcting operating
problems.
Operator Control Panel only displays one active code.
Only the most recent service code displays on the Operator
Control Panel. In troubleshooting, be alert for related codes.
Use of a diagnostic tool offers the advantages of spotting mul-
tiple active codes as well as retrieving historical codes.
A cleared code alone does not indicate a corrected
problem.
A code is set by a specific fault condition and may be cleared
by switching the ignition off. It's possible to clear a code (i.e.,
remove it from the driver interface) only to have it display
again when the fault condition reoccurs. To ensure that a
problem is fixed, you must run the system through the same
operating modes that caused the problem and verify that the
service code does not appear.
Disconnect the Electronic Control Unit connector with igni-
tion off.
To avoid setting electrical service codes, make sure that the
ignition is off before unplugging the wire harness connection
at the Electronic Control Unit module.
Reconnect the connector before switching on the ignition.
C! Service Codes are often connection problems.
The most likely cause of component faults will be damaged
wires or connections. As a first step in troubleshooting all C!
service codes, switch off vehicle ignition, then disconnect
applicable connectors and inspect for damage. (Switching off
the ignition is required before disconnecting the harness at
the Electronic Control Unit, but is also a recommended prac-
tice before all other electrical system disconnections.) Clean
or repair all suspicious connections before proceeding.
System is not continually pressurized.
When troubleshooting P! service code faults, keep in mind
that the air system is only pressurized as needed (for exam-
ple, in the inflate mode). This means that such procedures as
checking for leaks require the system to be in an active,
pressurized state. This can be accomplished most easily by
using a diagnostic tool.
Basic vehicle air and power systems are not covered in this
guide.
The Tire Pressure Control System requires air pressure and
electrical power supply from the base vehicle systems.
Diagnosis and service of these systems is outside the scope
of this manual.
Some faults will halt inflate or deflate sequences.
Upon sensing some service codes, the Tire Pressure Control
System will immediately go to the "maintain" mode. This may
cause mode arrows to stop flashing before the system has
actually attained the pressures for the indicated mode.