Diagnostic Trouble Code Response - PREVOST H3-41 Maintenance Manual

NOTE
Be sure to record all codes displayed before
they are cleared.
troubleshooting.
NOTE
If clearing a code while locked in a «D» (Drive)
or «R» (Reverse) position (fail-to-range), the
transmission will still be in «D» (Drive) or «R»
(Reverse) when the clearing procedure is
completed. «N» (Neutral) must be manually
selected.

6.1.5 Diagnostic Trouble Code Response

The electronic control system is programmed to
inform the operator of a problem with the
transmission system via the CHECK light and
shift selector display while it automatically takes
action to protect the operator, vehicle, and
transmission. When the Transmission Control
Module (TCM) flags a Diagnostic Trouble Code
(DTC) as active, the TCM may take a
combination of diagnostic responses as listed in
the following table.
CATEGORY OF RESPONSE
DNS - Do Not Shift
SOL OFF - SOLenoid
OFF
RPR - Return to
Previous Range
NNC - Neutral No
Clutches
DNA - Do Not Adapt
This is essential for
Release lock up (LU) clutch and inhibit lock up operation.
Inhibit shifts from the current attained range.
Turn on the CHECK light.
Display the current attained range in the MONITOR window of the shift
selector.
Blank the SELECT window of the shift selector.
Ignore any range selection inputs from the shift selector.
All solenoids are commanded off, resulting in hydraulic default operation of
the transmission – PCS1 & PCS2 are on hydraulically when off electrically.
When the speed sensor ratio or PS1 tests do not pass, the TCM commands
the same range as commanded before the shift.
When certain speed sensor ratio or PS1 tests do not pass, the TCM a
neutral condition with no clutches applied.
The TCM stops adaptive shift control while the code is active.
SECTION 07: TRANSMISSION
ACTIONS TAKEN
PA1621 Maintenance Manual All Series | January 2017
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