Honda BF40D Mode D'emploi page 444

• HO2S TROUBLESHOOTING
MIL blinks once
NOTICE
Use a known-good battery to connect the battery to the
connector terminal and take care not to short the circuit.
1) Symptom reproduction test
a. Turn the combination switch OFF. Disconnect
HO2S 4P connector
18
b. Reset the ECM and disconnect the SCS short
connector (P. 5-43).
c. Start the engine and let it run at 3,000 min
for 5 minutes or more under no load.
d. Run the engine at idle speed for one minute or
more.
e. Turn the combination switch OFF and connect the
SCS short connector.
f. Turn the combination switch ON and check the
number of blinks of the MIL.
Does the MIL blink once?
YES - Go to "2) Fuel supply system inspection."
NO - Temporary failure (Disappears).
2) Fuel supply system inspection
• Turn the combination switch OFF and measure the
fuel pressure (P. 5-80).
Is the fuel pressure normal?
YES - Go to "3) HO2S inspection."
NO - Recheck with the normal fuel pressure.
5-49
once and connect it again.
(rpm)
-1
444
3) HO2S inspection
a. Turn the combination switch OFF and disconnect
the HO2S 4P connector
b. Connect the battery positive (+) cable to the HO2S
side No.4 terminal (White) and the battery negative
(-) cable to the HO2S side No.3 terminal (White) of
the HO2S sensor 4P connector
c. Start the engine and let it run at 3,000 min
for 3 minutes or more under no load.
d. Snap the engine with the engine speed in the range
between the idle speed and 4,000
Measure the voltage between the HO2S side No.1
terminal (Black) and No.2 (Gray) terminal of the
HO2S 4P connector
18
HO2S 4P CONNECTOR HO2S SIDE
18
O2 (Black)
O2HT (White)
VIEWED FROM THE TERMINAL SIDE
Are the measurements 0.6V or more with the
throttle fully open and 0.4V or below with the
throttle fully closed?
YES - Go to "4) HO2S signal line short-circuit
inspection."
NO - Replace the HO2S with a new one and
recheck.
.
18
as shown.
18
(rpm)
-1
500 min (rpm).
-1
.
SG3 (Gray)
(White)
12V
BATTERY