WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
438
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
DTC P2771
Step
Action
Yes
No
Schematic Reference: Automatic Transmission Controls Schematics
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic
System Check - Vehicle
2
1. Install the scan tool.
2. Turn ON the ignition, with the engine OFF.
IMPORTANT:
Before clearing the DTC, use the scan tool in order to record the
Before clearing the DTC, use the scan tool in order to record the
Freeze Frame and Failure Records for reference. The Clear Info
Freeze Frame and Failure Records for reference. The Clear Info
function will erase the data.
function will erase the data.
3. Record the DTC Freeze Frame and Failure Records.
4. Clear the DTC.
5. Using the scan tool, monitor 4WD low status and select 4HI followed by 4LO
with the transfer case selector.
Does the scan tool indicate 4WD low status as NO when 4HI is selected, and YES
when 4LO is selected?
Go to Diagnostic Aids
Go to Step 3
3
Using the transfer case selector, select 4HI followed by 4LO.
Does the scan tool indicate 4WD low status as YES for both selector positions?
Go to Step 4
Go to Step 9
4
Remove the connector at the transfer case selector.
Does the scan tool indicate 4WD low status as YES?
Go to Step 5
Go to Step 7
5
Inspect the 4WD low signal circuit for a short to ground.
Did you find a condition?
Go to Step 6
Go to Step 15
6
Inspect and repair the short to ground in the 4WD low signal circuit. Refer to Circuit
Testing and Wiring Repairs .
Did you complete the repair?
Go to Step 16
—
7
Inspect the transfer case switch for proper operation or a short to ground. Refer to
Circuit Testing and Wiring Repairs .
Did you find a condition?
Go to Step 8
Go to Step 15
