C23" To Sensor Circuit Malfunction - Suzuki GSX-R750 Service Manual

4-44 FI SYSTEM AND INTAKE AIR SYSTEM

"C23" TO SENSOR CIRCUIT MALFUNCTION

DETECTED CONDITION
No TO sensor signal for more than 2 seconds,
after ignition switch turns ON.
Sensor voltage high.
0.25 V Sensor Voltage < 4.85 V
(
without the above range.
INSPECTION
• Lift and support the fuel tank with its prop stay. ( 4-51)
1
Turn the ignition switch OFF.
Check the TO sensor coupler for loose or poor contacts.
If OK, then measure the TO sensor resistance.
Disconnect the TO sensor coupler.
Measure the resistance between Black and B/W wire ter-
minals.
TO sensor resistance: 60 – 64 kΩ Ω Ω Ω Ω
[ 09900-25008: Multi circuit tester
U Tester knob indication: Resistance (Ω Ω Ω Ω Ω )
Yes
2
Connect the TO sensor coupler.
Insert the copper wires to the wire lead coupler.
Turn the ignition switch ON.
Measure the voltage at the wire side coupler between
Black and B/Br wires.
TO sensor voltage: Approx. 2.5 V (Black – B/Br)
Also, measure the voltage when leaning of the motorcycle.
Dismount the TO sensor from its bracket and measure
the voltage when it is leaned more than 43°, left and right,
from the horizontal level.
TO sensor voltage: 0 V (Black – B/Br)
[ 09900-25008: Multi circuit tester
V Tester knob indication: Voltage (
Yes
Black or B/Br wire open or shorted to ground, or poor n or s
connection. ( 4-25)
If wire and connection are OK, intermittent trouble or faulty ECM.
Recheck each terminal and wire harness for open circuit and
poor connection. ( 4-4)
)
(Black – B/W)
No Replace the TO sensor
with a new one.
)
No Loose or poor contacts on
the ECM coupler.
Open or short circuit in the
Black wire or B/Br wire.
Replace the TO sensor
with a new one.
Replace the ECM with a new
one, and inspect it again.
POSSIBLE CAUSE
• TO sensor circuit open or short.
• TO sensor malfunction.
• ECM malfunction.
1
2
V
Black Black
B/W B/W
B/Br B/Br
Black Black
ECM couplers