WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
262
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
DTC P0826
Step
Action
Value
Yes
No
4
1. Turn the ignition OFF.
2. Disconnect terminals 20 and 21 at the driver shift request switch.
3. Using the J 35616 GM terminal test kit, connect the DMM to terminal
21 and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Is the voltage within the specified range?
11.75-12.75 V
Go to Step 5
Go to Step 6
5
1. Turn the ignition OFF.
2. Using the J 35616 , connect the DMM to terminals 20 and 21 of the
driver shift request switch.
3. Operate the driver shift request switch in the Tap up and Tap down
position.
Is the resistance within the specified value?
OFF:
6.84 K ohms
Tap up:
1.87 K ohms
Tap down:
3.97 K ohms
Go to Step 7
Go to Step 9
6
IMPORTANT:
The condition that affects this circuit may exist in other con-
The condition that affects this circuit may exist in other con-
necting branches of the circuit. Refer to Power Distribution
necting branches of the circuit. Refer to Power Distribution
Schematics for complete circuit distribution.
Schematics for complete circuit distribution.
1. Inspect the ignition 0 voltage circuit for an open. Refer to Circuit
Protection - Fuses .
2. Replace the fuse if necessary.
Was the fuse open?
—
Go to Step 11
Go to Step 8
7
Test the signal circuit of the AT driver shift request switch for an open between
the AT driver shift request switch and the TCM. Refer to Testing for Continuity
and Wiring Repairs .
Did you find and correct the condition?
—
Go to Step 11
Go to Step 10
8
Test the ignition 0 voltage circuit of the AT driver shift request switch for an
open between the fuse block and the AT driver shift request switch. Refer to
Testing for Continuity and Wiring Repairs .
Did you find and correct the condition?
—
Go to Step 11
—
