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WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
347
2007 W Series Chassis
WSM082106
DTC P0964
Step
Action
Value
Yes
No
11
With the scan tool, observe the stored information, capture info, and
DTC Info.
Does the scan tool display any DTCs that you have not diagnosed?
—
Go to Diagnostic
Trouble Code
(DTC) List -
Vehicle
System OK
DTC P0966
Circuit Description
The pressure control solenoid 2 (PCS2) is a pressure
proportional to current (PCC) solenoid used to control
on-coming, off-going and holding pressure to any 1
of the 5 clutches. The transmission control module
(TCM) provides voltage to the PCS2, shift solenoid
1, 2, and 3 (SS1, SS2, and SS3) through a separate
solid-state device called high side driver 2 (HSD2). The
TCM regulates the amount of current to the PCS2 by
switching the low side driver ON and OFF.
DTC P0966 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
• DTC P0966 Pressure Control Solenoid 2 (PCS2) Control
Circuit Low (B)
Conditions for Running the DTC
• The components are powered and ignition voltage is
greater than 9.0 volts and less than 18 volts.
• TCM initialization is in process or engine speed is greater
than 200 RPM and less than 7,500 RPM for 5 seconds.
• Engine crank time is not extended.
• Associated HSD2 is enabled and no HSD2 codes are
active.
Conditions for Setting the DTC
DTC P0966 sets when the TCM detects a short to
ground on the PCS2 circuit for greater than 2 seconds.
Action Taken When the DTC Sets
• The TCM illuminates the malfunction indicator lamp
(MIL).
• If the failure occurs while in a forward range, a shift to
1st, 3rd or 5th range is made.
• While diagnostic response is active, if the shift selector
is moved to NEUTRAL, the transmission will shift to
NEUTRAL. If the shift selector is moved to REVERSE,
the transmission will shift to REVERSE. If the shift
selector is moved to a forward range or to REVERSE
and the transmission is compromised by overspeeding or
direction change, the transmission will shift to NEUTRAL.
• DTC P0966 is stored in TCM history.
• Main modulation (MAIN MOD) is inhibited.
• The TCM freezes shift adapts.
• The TCM inhibits torque converter clutch (TCC)
engagement.