
SRS –
Troubleshooting
52B-12
Code No.43 SRS warning lamp drive circuit system
(Lamp does not illuminate.)
Probable cause
This diagnosis code is output when an open circuit occurs for a continuous period
of 5 seconds while the SRS-ECU in monitoring the SRS warning lamp and the lamp
is OFF (transistor OFF).
However, if this code is output due to an open circuit, if the vehicle condition returns
to normal, this diagnosis code No.43 will be automatically erased, and the SRS warning
lamp will return to normal.
D
Malfunction of wiring harnesses or connectors
D
Blown bulb
D
Malfunction of SRS-ECU
D
Malfunction of combination meter
OK
Replace the combination
meter.
NG
Check the harness wire
between the SRS-ECU
and ignition switch (IG
1
).
NG
Repair
OK
Check trouble symptoms.
OK
Check the following
connectors:
B-51, B-09, B-08, B-75,
B-76
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
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
Connect terminal (15) to the body earth.
OK: Lamp illuminates
NG
Blown bulb inspection
NG
Repair
OK
Replace the SRS-ECU.
SRS check harness
(MB991613)
3
5
Code No.43 SRS warning lamp drive circuit system
(Lamp does not switch off.)
Probable cause
This diagnosis code is output when a short to earth occurs in the harness between
the lamp and the SRS-ECU while SRS-ECU is monitoring the SRS warning lamp
and the lamp is ON.
D
Malfunction of wiring harnesses or connectors
D
Malfunction of SRS-ECU
D
Malfunction of combination meter
SRS warning lamp inspection
D
Ignition switch: ON
D
Does lamp switch off when SRS-ECU connector B-51 is
disconnected?
No
Check the following
connectors:
B-51, B-09
NG
Repair
Yes
Replace the SRS-ECU.
OK
Check trouble symptoms.
NG
Check the harness wire
between the SRS-ECU
and combination meter,
and repair if necessary.