Allison Transmission Motorhome Series Operator's Manual page 63

If the MODE INDICATOR (LED) is illuminated, the displayed code is active. If
the mode indicator (refer to Figure 7 and Figure 8) is not illuminated, the
displayed code is not active. An illuminated mode indicator during normal
operation signifies secondary mode operation.
Diagnostic Codes—WTEC III Controls. When the diagnostic mode is entered,
the first code (position d1) is displayed as follows:
Example—Code 1312:
Displayed as: d, 1, 1, 3, 1, 2 (each item appears for about one second)
• d1 (code position)—Code position indicates that this is the first diagnostic
code listed in the ECU memory.
• 13 (main code)—Main codes (2 digits displayed one-at-a-time) are listed
first and provide the general condition or area of a fault detected by the
ECU.
• 12 (subcode)—Subcode (2 digits displayed one-at-a-time) are listed second
and provide specific areas or conditions within the main code that cause the
fault. This subcode indicates the problem is caused by low voltage.
Diagnostic Codes—Allison 4
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 and lever shift
selectors.
• d1 (code list position)—The position which a code occupies in the code list.
Positions are displayed as "d1" through "d5" (Code List Position 1 through
Code List Position 5).
• P0722 (DTC)—The diagnostic trouble code number referring to the general
condition or area of fault detected by the TCM.
th
Generation Controls. When the diagnostic mode
SELECT
d
0
2
MONITOR
1
P
7
2
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