MPI <4G63>
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Troubleshooting
13D-59
INSPECTION PROCEDURE 26
Check the engine-A/T-ECU power supply and earth circuit.
Measure the engine-A/T-ECU connectors, C-124, C-126.
D
Disconnect the connector and measure at the harness side
(1) Voltage between 98 and earth (Ignition switch: ON)
OK:
System voltage
(2) Voltage between 49 and earth
OK:
System voltage
(3) Voltage between 41, 47 and earth
OK:
System voltage (when the terminal 49 is earthed)
(4) Continuity between 42, 48 and earth
OK:
Continuity
(5) Voltage between 66 and earth
OK:
System voltage
(1) NG
Check
the
following
connectors:
C-14,
C-209, C
ï
210
NG
Repair
OK
Check the trouble symptom.
OK
Check the harness wire
betweenengine-A/T-ECU
and ignition switch con-
nector.
NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54
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Ignition Switch and Immobilizer System.)
(2), (3) NG
Check
the
following
connectors:
A-13,
B-16X, C-12
NG
Repair
OK
Check the trouble symptoms.
NG
Check the harness wire between engine-A/T-ECU and control relay
connector, and repair if necessary.
(4) NG
Check the harness wire between engine-A/T-ECU and earth, and
repair if necessary.
(5)
NG
OK
Check
the
following
connectors:
C-124, C-126
NG
Repair
OK
Check the trouble symptom.
NG
Replace the engine-A/T-ECU.
Check the harness wire between engine-A/T-ECU and battery,
and repair if necessary.
INSPECTION PROCEDURE 27
Power supply system and ignition switch-IG system
Probable cause
When an ignition switch ON signal is input to the engine-A/T-ECU, the engine-A/T-ECU
turns the engine control relay ON. This causes battery voltage to be supplied to the
engine-A/T-ECU, injectors and air flow sensor.
D
Malfunction of the ignition switch
D
Malfunction of the engine control relay
D
Improper
connector
contact,
open
circuit
or
short-circuited harness wire
D
Disconnected engine-A/T-ECU earth wire
D
Malfunction of the engine-A/T-ECU
Check the engine control relay. (Refer to P.13D-96.)
NG
Replace
OK
Measure at the engine control relay connector B-16X.
D
Disconnect the connector, and measure at the harness side.
D
Voltage between 3, 4 and earth
OK:
System voltage
NG
Check
the
following
connector:
A-13
NG
Repair
OK
Check the trouble symptom.
NG
Checktheharnesswirebetweenbatteryandcontrolrelayconnector,
and repair if necessary.
OK
Check the engine-A/T-ECU power supply and earth circuit.
(Refer to P.13D-59, INSPECTION PROCEDURE 26.)