WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
127
2007 W Series Chassis
WSM082106
DTC P0634
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, drive the vehicle and monitor TCM internal temperature.
Did DTC P0634 return?
Go to Step 3
Go to Diagnostic Aids
3
1. Inspect the TCM and surrounding area for obstructions.
2. Ensure the engine cooling fan is operating properly.
Do you find and correct the condition?
Go to Step 5
Go to Step 4
4
IMPORTANT:
In most cases, the TCM is not at fault. Investigate thoroughly before
In most cases, the TCM is not at fault. Investigate thoroughly before
replacing the TCM.
replacing the TCM.
Replace the TCM. Refer to Control Module References for replacement, setup, and
programming.
Did you complete the replacement?
Go to Step 6
—
5
Perform the following procedure in order to verify the repair:
1. Clear the DTC.
2. Start the engine.
3. Using the scan tool, drive the vehicle and monitor TCM internal temperature.
4. Select Specific DTC.
5. Enter DTC P0634.
Has the test run and passed?
Go to Step 6
—
