WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
144
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
DTC P0703
Step
Action
Value
Yes
No
3
1. Turn the ignition OFF.
2. Disconnect the 80-way connector at the TCM.
3. Install the J 39700 breakout box, the J-47275 breakout box
adapter and the J 47275-1 magnetic overlay.
4. Turn ON the ignition.
5. Using the DMM, measure voltage at connector terminal 2 and
ground.
6. Apply and release the service brake.
Is voltage within the specified value?
Brakes applied:
0.0V
Brakes released:
12.0 V
Go to Diagnostic
Aids
Go to Step 4
4
Using the DMM, measure voltage at terminal C of the stop lamp switch
and ground. Refer to Automatic Transmission Controls Schematics.
Is voltage within the specified value?
B+
Go to Step 5
Go to Step 6
5
Using the DMM, measure voltage at terminal D of the stop lamp switch.
Is voltage available?
B+
Go to Step 8
Go to Step 7
6
1. Remove the brake fuse.
2. Inspect the brake fuse for an open. Refer to General Electrical
Diagnosis Procedures .
Did you find and correct the condition?
—
Go to Step 9
—
7
Repair or replace the stop lamp switch. Refer to Stop Lamp Switch
Replacement .
Did you complete the repair or replacement?
—
Go to Step 9
—
8
Inspect the engine wiring harness for an open or short to ground. Refer
to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
—
Go to Step 9
—