C21" Iat Sensor Circuit Malfunction - Suzuki GSX1400 Service Manual

4-38 FI SYSTEM

"C21" IAT SENSOR CIRCUIT MALFUNCTION

DETECTED CONDITION
High intake air temp. (Low voltage – Low
resistance)
Low intake air temp. (High voltage – High
resistance)
INSPECTION
• Remove the right frame side cover. (
1
Turn the ignition switch OFF.
Check the IAT sensor coupler for loose or poor contacts.
If OK, then measure the IAT sensor voltage at the wire
side coupler.
Disconnect the coupler and turn the ignition switch ON.
Measure the voltage between Dg wire terminal and
ground.
If OK, then measure the voltage between Dg wire terminal
and B/Br wire terminal.
IAT sensor voltage: 4.5 – 5.5 V
09900-25008: Multi circuit tester
Tester knob indication: Voltage (
Yes
2
Turn the ignition switch OFF.
Measure the IAT sensor resistance.
IAT sensor resistance: Approx. 2.6 kΩ Ω Ω Ω Ω at 20°C (68°F)
09900-25008: Multi circuit tester
Tester knob indication: Resistance (Ω Ω Ω Ω Ω )
Yes
Dg or B/Br wire open or shorted to ground, or poor D or X
connection. ( 4-22)
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)
www.GSX1400FE.com
6-3)
+Dg – -Ground
( )
+Dg – -B/Br
)
No Loose or poor contacts on
the ECM coupler.
Open or short circuit in the
Dg wire or B/Br wire.
(Terminal – Terminal)
No Replace the IAT sensor
with a new one.
Replace the ECM with a new one,
and inspect it again.
ECM coupler
POSSIBLE CAUSE
• Dg circuit shorted to ground.
• B/Br circuit open.
• IAT sensor malfunction.
• ECM malfunction.
1
B/Br
Dg
2
Intake Air Temp.
20°C ( 68 °F)
50°C ( 122 °F)
80°C ( 176 °F)
110°C ( 230 °F)
NOTE:
IAT sensor resistance measurement
method is the same way as that of the EOT
sensor. Refer to page 5-11 for details.
V
Resistance
Approx. 2.6 kΩ
Approx. 0.8 kΩ
Approx. 0.3 kΩ
Approx. 0.2 kΩ