Lotus 2004 ELISE Service Notes page 425

Lotus Service Notes
System fault detection, SDM self test: min. 8.0 V; max. 16.0 V
Below 10.0 V system readiness may be delayed by 3 s.
Below 9.0 V system readiness may be delayed by 10 s.
System fault detection and SDM self test are reduced as long as an undervoltage condition is detected, which
could already apply for supply voltages below 10.5 V.
Activation of airbags: min. 8.0 V; max. 16.0 V.
Activation of seat belt pre-tensioners: min. 10.0 V; max. 16.0 V.
Energy Reserve
Energy reserve capacitors within the SDM are provided to allow SRS deployment if the vehicle battery
power supply is interrupted during the time of vehicle impact. The capacitors provide full support of the
acceleration sensing and airbag initiation capability for a minimum of 150 ms after a loss of external power
supply, provided that before the loss, the SDM had been supplied with:
at least 10.0 V for at least 10 s; or
at least 9.0 V for at least 13 s; or
at least 8.0 V for at least 20 s.
The capacitors will be discharged down to a point where no initiation of airbags is possible within a max.
of 20 s after removal of the power supply.
WD.8 - SENSOR & DIAGNOSTIC MODULE (SDM)
To Replace SDM
WARNING: The SDM must be replaced after SRS deployment. Do not attempt to repair or reuse.
The SDM is mounted on a bracket riveted to the top of the passenger side scuttle beam, and is accessible
only after removal of the fascia (dash) top panel.
1. Follow the safety procedure detailed in sub-section WD.6 to turn off the ignition, disconnect the battery
and unplug the yellow 4-way connector to the inflator module, alongside the steering column.
2. Column shrouds: Remove the two screws retaining the top part of the shroud, and the four screws
retaining the lower part, and withdraw both parts from the column.
3. Instrument shroud: Pull the instrument shroud backwards to release the four spring clips from their
apertures in the dash panel.
4. Sill top trims: Release the two screws at the bottom of the coin pockets at the front of each sill, and pull
the sill top trim panels from the chassis.
5. Dash end panels: Release the two screws within the top of each coin pocket, and withdraw the switch
panel (driver's side) and blanking panel (passenger side) from the dash end panel. Unplug the wiring
harness from the switch panel.
From within the aperture, release the two screws retaining each end panel to the dash, and pull the panel
rearwards to withdraw the spring clips in the top of the panel from the dash.
6. Airbag door: Pull the airbag door away from the dash, which action will probably require the four retaining
clips to be renewed. Note that the door is constrained by two tether straps.
WARNING:
•
The only permitted repair to the airbag door and tether strap assembly is the replacement of the
plastic retaining clips which secure the door to the dashboard. If the clips are broken, they MUST
be replaced ONLY by the correct Lotus supplied parts. Do not attempt to fix the door in position
by any other means.
•
After SRS deployment, the airbag door assembly MUST be replaced even if there is no visible
damage.
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Section WD