WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
293
2007 W Series Chassis
WSM082106
The ECM/PCM detects the Park/Neutral switch signal
equals 12 volts (high) when the IMS reports a Park/
Neutral range for 5 seconds.
DTC P0852
The ECM/PCM detects the Park/Neutral switch signal
equals 0 volts (low) when the IMS reports a Drive range
for 5 seconds and the following conditions are present:
• TP is equal to or greater than 6 percent.
• Engine torque is equal to or greater than 120 N·m (89 lb
ft).
• Vehicle speed is equal or greater than 24 km/h (15 mph).
Action Taken When the DTC Sets
• DTCs P0851 and P0852 are Type C DTCs.
• The ECM/PCM uses IMS range for engine start-up.
Conditions for Clearing the DTC
DTCs P0851 and P0852 are Type C DTCs.
Diagnostic Aids
It is possible for this DTC to set due to a stack-up or
misalignment issue between the IMS and the P/N
Switch, where no electrical fault is present. Ensure the
gear shift selector cable is properly adjusted and there
are no service bulletins that address this concern before
replacing parts.
Reference Information
• Schematic Reference
Automatic Transmission Controls Schematics
CONNECTOR END VIEW REFERENCE
• Automatic Transmission Inline Harness Connector End
View
• Automatic Transmission Internal Connector End Views
• Automatic Transmission Related Connector End Views
• Powertrain Control Module Connector End Views for
8.1L (L18)
DTC TYPE REFERENCE
• Diagnostic Trouble Code (DTC) Type Defi nitions
• Diagnostic Trouble Code (DTC) List/Type
ELECTRICAL INFORMATION REFERENCE
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
SCAN TOOL REFERENCE
• Scan Tool Data List
• Scan Tool Data Defi nitions
Circuit/System Verifi cation
If there are any other engine or transmission related
DTCs set, diagnose those DTCs fi rst. With a scan
tool observe the Park/Neutral switch parameter in the
engine controls data list and move the gear shift lever
from Park, to Reverse and through all the ranges and