
SRS –
Troubleshooting
52B-11
Code No.42 IG
1
(B) power circuit system
Probable cause
This diagnosis code is output if the voltage between the IG
1
(B) terminal and the
earth is lower than the specified value for a continuous period of 5 seconds or more.
However, if the vehicle condition returns to normal, diagnosis code No.42 will be
automatically erased, and the SRS warning lamp will switch off.
D
Malfunction of wiring harnesses or connectors
NG
Check the harness wire between the SRS-ECU and ignition switch
IG
1
, and repair if necessary.
OK
Check trouble symptoms.
OK
Replace the SRS-ECU.
OK
Measure at SRS check harness connector (5).
D
Disconnect SRS-ECU connector B-51.
D
Connect SRS check harness connector (3).
D
Ignition switch: ON
D
Voltage between terminal (13) and body earth
OK: 9 V or more
NG
Check the following
connectors:
B-51, B-78
NG
Repair
NG
Check the harness wire between the SRS-ECU and earth, and
repair if necessary.
OK
Check trouble symptoms.
Measure at SRS check harness
connector (5).
D
Disconnect SRS-ECU
connector B-51.
D
Connect SRS check
harness connector (3).
D
Continuity between
terminals (20)
OK: Continuity
NG
Check the following
connectors:
B-51, B-78, B-80
NG
Repair
SRS check harness
(MB991613)
3
5