MPI <4G6> -
Troubleshooting
13A-71
Inspection procedure 29
Ignition switch-ST system
Probable cause
The ignition switch-ST outputs a HIGH signal to the engine-ECU <M/T> or
engine-A/T
-ECU
<A/T>
while
the
engine
is
cranking.
The
engine-ECU
<M/T>
or
engine-A/T
-ECU
<A/T>
uses
this
signal
to
carry
out
functions such as fuel injection control during starting.
D
Malfunction of the ignition switch
D
Malfunction
of
the
inhibitor
switch
<A/T>
D
Open circuit or short-circuited harness wire of the
ignition switch circuit
D
Malfunction of the engine-ECU <M/T>
D
Malfunction
of
the
engine-A/T
-ECU
<A/T>
<M/T>
NG
Replace the engine-ECU.
OK
Check the trouble symptoms.
OK
Check the following connector:
C-40
NG
Repair
NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54.)
NG
Check the harness wire between the
engine-ECU and the ignition switch.
OK
Check the trouble symptoms.
NG
Check the following connectors:
C-92, C-105
NG
Repair
Measure at the engine-ECU connector
C-40.
D
Disconnect the connector, and
measure at the harness side.
D
Voltage between 71 and earth
(Ignition switch: START)
OK:
8 V or more
<A/T>
NG
Replace the engine-A/T-ECU.
OK
Check the trouble symptoms.
NG
Repair
OK
Check the following connector:
C-176
NG
Check the harness wire between inhibitor switch and engine-A/T-
ECU, and repair if necessary.
NG
Repair
OK
Check the trouble symptoms.
NG
Check the following connector:
B-72
OK
Measure at the engine-A/T-ECU connector C-176.
D
Disconnect the connector, and measure at the harness
side.
D
Voltage between 58 and earth
(Selector lever position: P or N)
(Ignition switch: START)
OK:
System voltage
NG
Repair
OK
Check the ignition switch (Refer to GROUP 54 – Ignition Switch.)
NG
Check the harness wire between inhibitor switch andignitionswitch.
NG
Repair
OK
Check the trouble symptoms.
NG
Check the following connectors:
C-92, C-105
OK
Measure at the inhibitor switch connector B-72.
D
Disconnect the connector, and measure at the harness
side.
D
Voltage between 10 and earth (Ignition switch: START)
OK:
System voltage
Check the inhibitor switch
D
Continuity between 9 and 10 (Refer to GROUP 23 –
On-vehicle service.)
NG
Replace
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