Page 3 of 40
88C-3V1 MR-376-X76-88C000$010.mif
AIRBAGS AND PRETENSIONERS
Fault finding – Introduction88C
2nd generation
(AC4 phase II)
Special tooling required:
4. REMINDERS
During operations on the airbag/seat belt pretensioner systems it is vital that you lock the computer using the
diagnostic tool to prevent any risk of accidental triggering (all the trigger lines will be inhibited). The locked mode is
indicated when the instrument panel warning light comes on. Without the diagnostic tool, switch off the ignition and
remove the supply fuse from the system, then wait at least 2 seconds for the power reserve capacity to discharge.
Never measure the airbag or pretensioner trigger lines with any device other than the XRBAG or by the "Airbag and
pretensioner wiring harness check" function on the CLIP and NXR tools.
Before using a dummy ignition module, check that its resistance is between 1.8 and 2.5 ohms.
Ensure during the operation that the supply voltage to the computer does not drop below 10 volts.Special tooling required
Diagnostic tools (except XR25)
Adapter and bornier kit to be used for the "Airbag and
pretensioner wiring harness check" function of the CLIP and
NXR tools or the XRBAG unit.
Multimeter
Page 13 of 40
88C-13V1 MR-376-X76-88C000$040.mif
88C
2nd generation
(AC4 phase II)
REPLACING THE AIRBAG COMPUTER
The airbag computers are sold in locked mode to avoid all risk of accidental triggering (all ignition lines are inhibited).
The "locked" mode is indicated when the airbag fault warning indicator light on the instrument panel illuminates.
Follow this procedure when replacing an air bag computer:
– Make sure the ignition is switched off.
– Replace the computer (see MR Mechanical: MR-AIRBAGS-SRP, 88, Airbags and seat belt pretensioners,
Computer: Removal-refitting).
– Carry out a check using the diagnostic tool.
– If necessary, modify the computer configuration using the "Configuration" command.
– Switch off the ignition.
– Unlock the computer only if no faults are indicated by the diagnostic tool.
WARNING:
The owner of the vehicle may have locked the passenger front airbag to allow a child seat to be fitted to
the front passenger seat. In this case, the procedure for locking the passenger front airbag defined in the
Technical Note published for this subject has been applied, i.e.:
– Signing of a discharge by the customer (example in the Technical Note).
– Replacement of the passenger front seat belt.
– Disconnection of the passenger front airbag module.
– Locking of the trigger line of the passenger front airbag and modification of the computer configuration.
– Replacement of the "airbag" labels on the passenger side.
If this procedure has been applied, it is imperative to relock the passenger front airbag using the "Lock
passenger front airbag" command ("Configuration and programming" section).
It is vital that you never use this passenger airbag locking command before a Technical Note dealing with
the subject has been distributed.
AIRBAGS AND PRETENSIONERS
Fault finding – Replacement of components
Page 24 of 40
88C-24
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-88C000$060.mif
AIRBAGS AND PRETENSIONERS
Fault finding – Interpretation of faults88C
2nd generation
(AC4 phase II)
DF010
CONTINUED
Warning light off when ignition on
Lock the computer using the command on the diagnostic tool.
Check the condition of the warning light bulb.
Ensure the continuity of the connection between the warning light and track 7 of the 30-track connector.
Confirm the presence of 12 volts at the warning light.
If the checks carried out did not reveal the presence of a fault, disconnect the computer connector and fit the B40
30-track adapter. Use the CLIP, NXR or XRBAG tools to test the operation of the instrument panel warning light
from the grey cable marked 1 on the adapter.
If it is possible to illuminate the warning light using the tool, replace the airbag computer (refer to the section
"Replacement of components" for this operation).
If it is impossible to operate the warning light, repeat the preceding checks.
Warning light on when ignition on
Lock the computer using the command on the diagnostic tool.
Disconnect the airbag computer and check the base for the 5 pins that open the connector shunts.
Ensure the insulation to earth of the connection between the warning light and track 7 of the 30-track connector.