Suzuki GSX-R750, Service Manual

Page: 183 / 495

4-36 FI SYSTEM AND INTAKE AIR SYSTEM
B/Br
Red
V
V
Red
INSPECTION
• Lift and support the fuel tank with its prop stay. (
4-51)
Turn the ignition switch OFF.
Check the IAP sensor coupler for loose or poor contacts.
If OK, then measure the IAP sensor input voltage.
Disconnect the IAP sensor coupler.
Turn the ignition switch ON.
Measure the voltage at the Red wire and ground.
If OK, then measure the voltage at the Red wire and B/Br
wire.
IAP sensor input voltage: 4.5 – 5.5 V
(
+
Red –
-
Ground )
+
Red –
-
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 Red wire or B/Br wire.
Yes
Connect the IAP sensor coupler.
Insert the copper wires to the lead wire coupler.
Start the engine at idling speed.
Measure the IAP sensor output voltage at the wire side
coupler (between G/B and B/Br wires).
IAP sensor output voltage: Approx. 2.7 V at idle
speed (
+
G/B –
-
B/Br)
09900-25008: Multi circuit tester
Tester knob indication: Voltage ( )
No Check the vacuum hose
for crack or damage.
Open or short circuit in
the G/B wire.
Replace the IAP sensor
with a new one.
Yes
“C13” IAP SENSOR CIRCUIT MALFUNCTION
DETECTED CONDITION POSSIBLE CAUSE
Low pressure and low voltage. • Clogged vacuum passage between throttle
High pressure and high voltage. body and IAP sensor.
0.5 V Sensor voltage < 4.85 V • Air being drawn from vacuum passage
(
without the above range.
)
between throttle body and IAP sensor.
NOTE:
• Red wire circuit open or shorted to ground.
Note that atmospheric pressure varies depending
• B/Br or G/B wire circuit shorted to ground.
on weather conditions as well as altitude. • IAP sensor malfunction.
Take that into consideration when inspecting voltage.
• ECM malfunction.
1
1
1
2
V
G/B G/B B/Br B/Br
2