WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
302
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
DTC P0873
Step
Action
Yes
No
6
1. Turn the ignition OFF.
2. Disconnect the AT inline 20-way connector. Additional DTCs may set.
3. Install the J 44152 jumper harness (20 pins) on the engine side of the AT inline
20-way connector.
4. Turn ON the ignition, with the engine OFF.
5. Using the J 35616 GM terminal test kit and a fused jumper wire, connect termi-
nal E of the J 44152 to ground. Refer to Automatic Transmission Inline Harness
Connector End View .
Does the scan tool indicate PS3 status is LOW when grounded and HIGH when open?
Go to Step 7
Go to Step 14
7
1. Connect the AT inline 20-way connector.
2. Remove the transmission oil pan. Refer to Oil Pan Replacement .
3. Disconnect the AT internal wiring harness from the PSM and ground terminal
C.
Does the scan tool indicate PS3 status is LOW when grounded and HIGH when open?
Go to Step 8
Go to Step 13
8
1. Remove the PSM from the control valve body and leave the internal harness
connected. Refer to Pressure Switch Manifold Replacement .
2. Provide a ground connection for the PSM to either the control valve body or the
transmission main case.
3. Using the eraser end of a pencil, push gently on the PS3 membrane.
Does the scan tool indicate PS3 status is LOW when grounded and HIGH when open?
Go to Step 9
Go to Step 12
9
Remove the control valve body and inspect for a stuck or sticking shift valve 3. Refer
to Control Valve Body Disassemble.
Was the shift valve 3 stuck or sticking?
Go to Step 11
Go to Step 10
10
Replace the SS3 and install the control valve body. Refer to Control Valve Body
Replacement .
Did you complete the solenoid replacement and installation of the valve body?
Go to Step 16
—
11
Clean and/or polish the sticking valve to restore free movement or replace the control
valve body assembly. Refer to Control Valve Body Replacement .
Did you restore free movement or replace the valve body?
Go to Step 16
—