Section 07: TRANSMISSION
PA1562
21
9.3 DIAGNOSTIC CODES – ALLISON 4
TH
GENERATION CONTROLS
When the diagnostic mode is entered, the first
code (position d1) is displayed as follows:
Example: Code P0722
Displayed as: d1…P…07…22
The code list position is the first item displayed,
followed by the DTC. Each item is displayed for
about one second. The display cycles
continuously until the next code list position is
accessed by pressing the MODE button. The
following example shows how DTC P0722 is
displayed on the pushbutton shift selector.
d 1
P
0 7
SELECT
2 2
MONITOR
• d1 (code list position) – The position which a code
occupies in the list. Positions are displayed as
« d1 » through « d5 » (code list position 1 through
code list position 5).
• P0722 (DTC) – The diagnostic troubleshooting
code number referring to the general condition or
area of fault detected by the TCM.
9.4 DIAGNOSTIC CODE DISPLAY AND
CLEARING PROCEDURE – ALLISON
4
TH
GENERATION CONTROLS
Diagnostic codes can be read and cleared by
two methods:
o Using an Allison DOC™ diagnostic tool. For
specific instructions on how to use an Allison
DOC™ diagnostic tool, refer to the User
Guide.
o Using the pushbutton shift selector.
To begin the diagnostic process:
1. Bring the vehicle to a stop at a safe location.
2. Apply the parking brake.
To display stored codes:
1. Simultaneously press the
(Up) and
(Down) arrow buttons twice to access the
Diagnostic Display Mode.
NOTE
To access the Oil Level Display Mode,
simultaneously press the
(Up) and
(Down) arrow buttons once. Consult
paragraph: « ALLISON TRANSMISSION OIL
LEVEL CHECK USING THE PUSHBUTTON
SHIFT SELECTOR » at the end of this
section.
2. Observe the digital display for code (d1).
3. Press the MODE button to see the next
code (d2) – repeat for subsequent codes
(d3, d4 & d5).
NOTE
Be sure to record all codes displayed before
they are cleared. This is essential for
troubleshooting.
NOTE
The Diagnostic Display Mode can be entered
for viewing codes at any speed. Codes can
only be cleared when the output speed = 0
and no output speed sensor failure is active
Active indicators (MODE INDICATOR LED) and
inactive codes can be cleared manually, while in
the diagnostic display mode, after the condition
causing the code is identified.
To clear active indicators and inactive codes:
1. While in Diagnostic Display Mode, press
and hold the MODE button for 10 seconds
to clear both active indicators and inactive
codes.