FUEL SYSTEM <4D5-step
III
> -
Troubleshooting
13-30
INSPECTION PROCEDURES FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
No communication can be established between MUT-
II
and all systems.
Probable cause
Probable cause can be found in troubles with the power supply circuit and the
earth circuit to the diagnosis connector.
D
Diagnosis connector inoperative
D
Harness inoperative
OK
OK
Replace MUT-
II
.
NG
Check and repair the harness
between the power supply and
diagnosis connector.
OK
Check the trouble symptoms.
NG
Repair
NG
Check the following connectors:
C-108, C-103, A-19X, C-101
NG
Measure at C-113 diagnosis
connector.
D
Voltage between 16 and the
earth
OK:
System voltage
Measure at C-113 diagnosis
connector.
D
Continuity between 4 and the
earth
D
Continuity between 5 and the
earth
OK:
Continuity
Check and repair the earth line.
INSPECTION PROCEDURE 2
No communication can be established between MUT-
II
and the engine-ECU.
Probable cause
Probable causes are shown in the following:
D
The power is not supplied to the engine-ECU.
D
The earth circuit of the engine-ECU inoperative
D
The engine-ECU inoperative
D
Communication between the engine-ECU and MUT-
II
inoperative
D
The power supply circuit of the engine-ECU
inoperative
D
Engine-ECU inoperative
D
Open circuit at the harness between the
engine-ECU and the diagnosis connector
NG
Check the harness between the engine-ECU and diagnosis
connector.
NG
Repair
OK
Check the trouble symptoms.
Check the following connectors:
C-75, C-24, C-130
NG
Repair
OK
The engine-ECU power supply and the earth circuit check
(Refer to P.13-37, Inspection procedure 21.)