C13" Iap Sensor Circuit Malfunction - Suzuki GSX-R750 Service Manual

4-36 FI SYSTEM AND INTAKE AIR SYSTEM

"C13" IAP SENSOR CIRCUIT MALFUNCTION

DETECTED CONDITION
Low pressure and low voltage.
High pressure and high voltage.
(
0.5 V Sensor voltage < 4.85 V
without the above range.
NOTE:
Note that atmospheric pressure varies depending
on weather conditions as well as altitude.
Take that into consideration when inspecting voltage. • ECM malfunction.
INSPECTION
• Lift and support the fuel tank with its prop stay. ( 4-51)
1 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
[ 09900-25008: Multi circuit tester
V Tester knob indication: Voltage (
Yes
2
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
[ 09900-25008: Multi circuit tester
V Tester knob indication: Voltage (
Yes
)
+Red – -Ground
(
+Red – -B/Br
)
No Loose or poor contacts on
the ECM coupler.
Open or short circuit in
the Red wire or B/Br wire.
speed (+G/B – -B/Br)
)
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.
POSSIBLE CAUSE
• Clogged vacuum passage between throttle
body and IAP sensor.
• Air being drawn from vacuum passage
between throttle body and IAP sensor.
• Red wire circuit open or shorted to ground.
• B/Br or G/B wire circuit shorted to ground.
• IAP sensor malfunction.
1
)
V
1
V
2
Red
B/Br
Red
G/B G/B B/Br B/Br
V