Suzuki TU250X, Руководство по обслуживанию, Страница: 180 / 370

FI SYSTEM DIAGNOSIS 4-59
Step 2
1) Turn the ignition switch OFF.
2) Connect the STP sensor coupler.
3) Insert the needle-point probes to the STP sensor coupler.
4) Disconnect the STVA lead wire coupler
1
.
5) Turn the ignition switch ON.
6) Measure the STP sensor output voltage at the coupler
(between
+
Y wire and
-
B wire) by turning the fast idle cam
2
(secondary throttle valve close and open) with a finger.

STP sensor output voltage
Secondary throttle valve is closed : Approx. 0.5 V
Secondary throttle valve is opened: Approx. 3.9 V

09900-25008: Multi circuit tester set
09900-25009: Needle-point probe set

Tester knob indication: Voltage (

)
Is the voltage OK?
2
2
Close
Open
YES
• R, Bl/Y or B/Br wire open or shorted to ground,
or poor
A
,
J
or
T
connection
• If wire and connection are OK, intermittent trou-
ble or faulty ECM.
• Recheck each terminal and wire harness for
open circuit and poor connection.
• Replace the ECM with a known good one, and
inspect it again.
NO
• Short circuit in the Bl/Y wire
• If check result is not satisfactory, replace STP
sensor with a new one.
ECM coupler (Harness side)
2