Mitsubishi FUEL Manual page 170

13A-170
INSPECTION PROCEDURE 26
Engine-ECU power supply and earth circuit system
The engine-ECU may be defective, or that one of the malfunctions listed at right
has occurred.
Measure at the engine-ECU connectors C-167, C-166.
D Disconnect the connector and measure at the harness side
(1) Voltage between 99 and earth (Ignition switch: ON)
OK: System voltage
(2) Voltage between 57 and earth
OK: System voltage
(3) Voltage between 59, 47 and earth (Ignition switch: ON)
OK: System voltage (when the terminal 57 is earthed)
(4) Continuity between 46, 58 and earth
OK: Continuity
(5) Voltage between 60 and earth
OK: System voltage
OK
NG
Check the following
connectors:
C-167, C-166
OK
Check trouble symptom.
NG
Replace the engine-ECU.
MPI <6A1> -
(1) NG
(2), (3) NG
(4) NG
(5) NG
Repair
Troubleshooting
Probable cause
D Improper
short-circuited harness wire in the engine-ECU power
supply circuit.
D Open circuit or short-circuited harness wire in the
engine-ECU earth circuit
D Malfunction of the engine-ECU
Check the following
connectors:
C-92, C-131
OK
Check trouble symptom.
OK
Check the harness wire
between engine-ECU
and ignition switch
connector.
OK
Check the ignition switch.
(Refer to GROUP 54 - Ignition Switch.)
Check the harness wire between engine-ECU and control relay
connector, and repair if necessary.
Check the harness wire between engine-ECU and earth, and repair
if necessary.
Check the following
connectors: C-47, C-83,
C-66, C-63, C-132, C-141
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and battery, and
repair if necessary.
connector contact, open circuit
NG
Repair
NG
Repair
NG
Repair
or