Mitsubishi Electric Lancer Evolution-VII Workshop Manual page 543

52B-12
Code No.21 Driver's air bag module (squib) system
This code is output when short circuit occurs between terminals of the
SRS-ECU driver's air bag module (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)
NO TE:
(1) *: The connector of the squib circuit contains a short bar (short-circuiting the positive (+) cable and
the negative ( - ) cable to avoid an erroneous deployment caused by static electricity when a connector
is not connected). Thus, when a connector is connected, the short bar may not be released due
to improper engagement of the connector or faulty connector as shown in the illustration below.
Disconnect the connector as shown in the illustration below, then reconnect it. Check that a diagnosis
code is output again after erasing the memory. If the diagnosis code is not output, the above-mentioned
code is output due to improper engagement of the connector.
(2) Two different types of driver's air bag modules by model are featured. Thus, two types of air bag
module by model are described in the following flowchart.
RS: Steering wheel and air bag module separate type
RS-II: Steering wheel and air bag module incorporate type
SRS -
C-21
C-204
SRS-ECU
Clock spring
<RS>
Troubleshooting
Possible Cause
D Connector engagement faulty or short bar faulty*
D Short circuit in the clock spring
D Short circuit between terminals of the driver's air
bag module (squib) circuit
D Faulty connector
D SRS-ECU inoperable
C-207
Driver's air bag module
<RS-II>