WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
405
2007 W Series Chassis
WSM082106
DTC P2723
Circuit Description
Pressure control solenoid 1 (PCS1) is used to control
on-coming, off-going, and holding pressure in any 1 of
5 clutches. This solenoid is referred to as a pressure
proportional to current (PPC) solenoid, since the
output hydraulic pressure supplied by this solenoid is
proportional to the controlled current command.
The transmission control module (TCM) uses
information from the turbine and output speed sensors to
detect if a clutch is slipping. The clutch being controlled
by PCS1 will vary depending on the shift that was being
completed.
DTC P2723 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
• DTC P2723 Pressure Control Solenoid 1 (PCS1)
Controlled Clutch Stuck Off
Conditions for Running the DTC
• The components are powered and ignition voltage is
greater than 9.0 volts and less than 18 volts.
• Turbine speed is greater than 60 RPM.
• Output speed is greater than 125 RPM.
• The transmission is at normal operating temperature.
Conditions for Setting the DTC
DTC P2723 sets when the TCM detects an incorrect on-
coming ratio for an accumulated number of occurrences
during a forward range shift.
Action Taken When the DTC Sets
• The TCM illuminates the malfunction indicator lamp
(MIL).
• When failure occurs in a forward range, the transmission
will go to the previous range. If failure occurs in
NEUTRAL or REVERSE, the transmission will lock in
NEUTRAL while diagnostic response is active.
• If the shift selector is moved to NEUTRAL, the
transmission will shift to NEUTRAL, and in some cases
may lock in NEUTRAL.
• If the shift selector is moved to REVERSE, the
transmission will shift to REVERSE or NEUTRAL.
• If the shift selector is returned to a forward range and
the transmission is compromised by overspeeding or
direction change, the transmission will shift to NEUTRAL.
• DTC P2723 is stored in TCM history.
• The TCM freezes shift adapts.
• The TCM inhibits torque converter clutch (TCC)
engagement.
Conditions for Clearing the DTC
A scan tool can clear the code from TCM history. The
TCM automatically clears the DTC from TCM history if
the vehicle completes 40 warm-up cycles without failure.