Mitsubishi Grandis. Manual - part 998
TROUBLESHOOTING
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-44
CAUTION
If diagnosis code B1410 <1st squib> or B1490
<2nd squib> is set in the SRS-ECU, always
diagnose the CAN main bus line.
OPERATION
• The SRS-ECU judges how severe a collision is
by detecting signals from the front impact sensors
and the front air bag analog G-sensor. If the
impact is over a predetermined level, the
SRS-ECU sends an ignition signal. At this time, if
the front air bag safing G-sensor is on, the SRS
air bag will inflate.
• The ignition signal is input to the air bag module
via the clock spring to inflate the air bag.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if there is abnormal
resistance between the input terminals of the
passenger's side air bag module (squib). However, if
no diagnosis code reset, the SRS warning lamp will
be switched off (diagnosis code will be retained).
PROBABLE CAUSES
• Improper engaged connector or defective short
spring*
• Short circuit between the passenger's air bag
module (squib) circuit terminals
• Damaged connector(s)
• Malfunction of the SRS-ECU
NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the air bag from
deploying unintentionally due to static electricity by
shorting the positive wire to the earth wire in the
squib circuit when the connectors are disconnected).
(Refer to
). Therefore, if connector C-119 or
C-108 is damaged or improperly engaged, the short
spring may not be released when the connector is
connected.
DIAGNOSIS PROCEDURE
STEP 1. MUT-III CAN bus diagnostics
Use the MUT-III to diagnose the CAN bus lines.
Q: Is the check result normal?
YES :
Go to Step 2.
NO :
Repair the CAN bus line (Refer to GROUP
54D, Diagnosis
STEP 2. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is
not reset.
Q: Is the diagnosis code set?
YES :
Go to Step 3.
NO :
There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction
).
STEP 3. MUT-III diagnosis code
CAUTION
To prevent damage to MUT-III, always turn the
ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting MUT-III.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the diagnosis code is set.
(3) Turn the ignition switch to the "LOOK" (OFF)
position.
Q: Is diagnosis code B1519 set?
YES :
Go to Step 4.
NO :
Go to Step 5.
STEP 4. Connector check: SRS-ECU connector
C-119
Q: Is the connector correctly engaged?
YES :
Go to Step 5.
NO :
Engage the connector correctly. Then go to
Step 9.