Technical data

55
Electronic control
Control unit/shifting strategies
The low range additional shift stage must
only be used with the engine running.
If the engine is switched off while in low
range, low range will automatically be
switched OFF when it is restarted and the
clutch is actuated.
This will prevent unnecessary low range
operation.
If the engine is stalled and restart within
15 seconds, low range will be retained (no
automatic OFF).
It is assumed that the driver would prefer this,
in this situation.
Fitting location:
The additional shift stage control unit J554 is
located in the housing box below the carpet
in front of the passenger seat (instead of
the control unit for the automatic gearbox).
Control unit run-on
For safety reasons, the control unit J554
remains active for approx. 30 seconds after
ignition “OFF“ (via terminal 30).
If the additional shift stage is in the neutral
position before switching off the engine
(ignition “OFF”, e.g. due to an incomplete
shift operation), there will be no power
transmission from the engine to the wheels,
despite a gear having been selected.
A vehicle parked in this way is not protected
against rolling away.
The run-on enables the control unit to
recognise this situation and switch low range
OFF after the ignition "OFF" (without
actuating the clutch).
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