WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
139
2007 W Series Chassis
WSM082106
DTC P0701
Circuit Description
The transmission control module (TCM) monitors the
status of the pressure switches at start-up, in order to
detect the presence of hydraulic pressure.
DTC P0701 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
• DTC P0701 Transmission Control System Performance
Conditions for Running the DTC
• The components are powered and ignition voltage is
greater than 9.0 volts and less than 18 volts.
• Engine speed is greater than 200 RPM and less than
7,500 RPM for 5 seconds.
Conditions for Setting the DTC
DTC P0701 sets when the TCM detects the following
conditions:
• Transmission fl uid temperature is greater than -25°C (-
13°F).
• All pressure switches do not indicate pressure at start-
up.
• Engine speed is greater than 500 RPM for 6 seconds or
400 RPM for 15 seconds.
• Forward or REVERSE range is selected.
Action Taken When the DTC Sets
• The TCM does not illuminate the malfunction indicator
lamp (MIL).
• DTC P0701 is stored in TCM history.DTC P0701 is
stored in TCM history.DTC P0701 is stored in TCM
history.
• The TCM inhibits torque converter clutch (TCC)
engagement.
Conditions for Clearing the DTC
• A scan tool can clear the code from TCM history. The
TCM automatically clears the DTC from TCM history if
the vehicle completes 40 warm-up cycles without failure.
Diagnostic Aids
• Inspect the wiring for poor electrical connections at the
TCM. Inspect for the following conditions:
– A bent terminal
– A backed-out terminal
– A damaged terminal
– Poor terminal tension
– A chafed wire
– A broken wire inside the insulation
• When diagnosing for an intermittent short or open,
massage the wiring harness while watching the test
equipment for a change.
• You may have to drive the vehicle in order to experience
a condition.
• DTC P0701 may be logged if a forward or REVERSE
range is selected immediately after the engine is started,
and before the TCM detects pressure at the switches, 2-