Diagnostic Trouble Code Response - PREVOST H3-45 VIP Owner's Manual

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 table below.
RESPONSE CATEGORY
DNS - Do Not Shift
SOL OFF - Solenoid OFF
RPR - Return to Previous
Range
NNC - Neutral No Clutches
DNA - Do Not Adapt
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
commands a neutral condition with no clutches applied.
The TCM stops adaptive shift control while the code is active.
PA-1619 Owner's Manual H3-45 VIP
Allison Transmission Other Features C-9
ACTIONS TAKEN