Suzuki GSX-R750, Service Manual

Page: 187 / 495

4-40 FI SYSTEM AND INTAKE AIR SYSTEM
B/Br
B/Bl
V
Engine Coolant
Resistance
Temp.
20°C ( 68 °F) Approx. 2.45 k
Ω
50°C ( 122 °F) Approx. 0.811 k
Ω
80°C ( 176 °F) Approx. 0.318 k
Ω
110°C ( 230 °F) Approx. 0.142 k
Ω
INSPECTION
• Lift and support the fuel tank with its prop stay. (
4-51)
Turn the ignition switch OFF.
Check the ECT sensor coupler for loose or poor contacts.
If OK, then measure the ECT sensor voltage at the wire
side coupler.
Disconnect the coupler and turn the ignition switch ON.
Measure the voltage between B/Bl wire terminal and
ground.
If OK, then measure the voltage between B/Bl wire termi-
nal and B/Br wire terminal.
ECT sensor voltage: 4.5 – 5.5 V
(
+
B/Bl –
-
Ground )
+
B/Bl –
-
B/Br
09900-25008: Multi circuit tester
Tester knob indication: Voltage ( )
No Loose or poor contacts on
the ECM coupler.
Open or short circuit in the
B/Bl wire or B/Br wire.
Yes
Turn the ignition switch OFF.
Measure the ECT sensor resistance.
ECT sensor resistance: 2.3 – 2.6 k
Ω Ω Ω Ω Ω
at 20°C (68°F)
(Terminal – Terminal)
09900-25008: Multi circuit tester
Tester knob indication: Resistance (
Ω Ω Ω Ω Ω
)
Refer to page 5-8 for details.
No Replace the ECT sensor
with a new one.
Yes
B/Bl or B/Br wire open or shorted to ground, or poor
k
or
n
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)
Replace the ECM with a new one,
and inspect it again.
“C15” ECT SENSOR CIRCUIT MALFUNCTION
DETECTED CONDITION POSSIBLE CAUSE
High engine coolant temp. (Low voltage – Low • B/Bl circuit shorted to ground.
resistance) • B/Br circuit open.
Low engine coolant temp. (High voltage – High • ECT sensor malfunction.
resistance) • ECM malfunction.
1
2
1
2
ECM couplers