WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
436
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
DTC P2764
Step
Action
Value
Yes
No
11
Perform the following procedure in order to verify the repair:
1. Clear the DTC.
2. Drive the vehicle under normal operating conditions.
3. Select Specific DTC.
4. Enter DTC P2764.
Has the test run and passed?
—
Go to Step 12
Go to Step 2
12
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 P2771
Circuit Description
The four-wheel drive (4WD) low signal circuit is used to
notify the transmission control module (TCM) that the
vehicle is in 4WD low range.
DTC P2771 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
• DTC P2771 4WD Low Switch Circuit
Conditions for Running the DTC
• DTCs P0721 and P0722 are not active.
• The components are powered and ignition voltage is
greater than 9.0 volts and less than 18 volts.
• Engine speed is greater than 200 RPM and less than
7,500 RPM for 5 seconds.
• Output speed is greater than 60 RPM.
• Transmission fl uid temperature (TFT) is between 20-
130°C (68-266°F).
• The shift is complete and NEUTRAL range is not
selected.
Conditions for Setting the DTC
DTC P2771 sets when one of the following conditions
occur:
• The transfer case switch indicates high range, and the
calculated range is low range for 5 seconds or greater.
• The transfer case switch indicates low range, and the
calculated range is high range for 5 seconds or greater.
Action Taken When the DTC Sets
• The TCM illuminates the malfunction indicator lamp
(MIL) during the second consecutive trip in which the
Conditions for Setting the DTC are met.
