Possible Cause - Mitsubishi Electric Lancer Evolution-VII Workshop Manual

52B-22
Code No.25 Front passenger's air bag module (squib)
system
This code is output when open circuit occurs in the SRS-ECU front passenger's
air bag (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)
Dummy resistor
(MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
<Check the circuit between the SRS-ECU and the front
passenger's air bag module>
Measure at the SRS-ECU connector C-21 and front
passenger's air bag module connector C-109 .
D Disconnect the SRS-ECU connector C-21 and the front
passenger's air bag module connector C-109 , and
measure at the harness side.
D Continuity check between the following terminals
Connector C-21
9 –
10 –
Caution
Do not directly insert a probe or other devices at the
front of the connector to avoid a possible decrease in
the contact pressure.
OK: Continuity (2Ω or less)
Connector C-109
Connector C-21
Replace the SRS-ECU.
SRS -
Resistor harness
(MB991866)
Front passenger's air bag
module connector
YES
Connector C-109
2
1
OK
Troubleshooting

Possible Cause

D Open in the front passenger's air bag module
(squib) circuit
D Connector improper contact
D SRS-ECU inoperable
<Check the front passenger's air bag module (squib)>
MUT-II self-diag code
D Connect the dummy resistor (MB991865) to the resistor harness
(MB991866).
D Disconnect the front passenger's air bag module connector C-109
and insert the resistor harness (MB991866) behind the harness side
connector.
Caution
Do not directly insert a probe or other devices at the front of the
connector to avoid a possible decrease in the contact pressure.
D Connect the negative (- ) terminal of the battery
D Check the diagnosis code again after erasing the memory.
Is code No.25 output?
Replace the front passenger's seat air bag module (squib).
NG
Check connector: C-21, C-109
OK
Check the trouble
symptoms.
NG
Check the harness between the front passenger's air bag
module and the SRS-ECU, and repair if necessary.
NO
NG
Correct