Suzuki TU250X Service Manual page 178

4) Disconnect the STP sensor coupler.
5) Turn the ignition switch ON.
6) Measure the voltage at the R wire A and ground.
7) Also, measure the voltage at the R wire A and B/Br wire C.
 STP sensor input voltage: 4.5 – 5.5 V
 09900-25008: Multi circuit tester set
 Tester knob indication: Voltage ()
Is the voltage OK?
YES Go to Step 2.
• Loose or poor contacts on the ECM coupler
(terminal A or T)
NO
• Open or short circuit in the R wire or B/Br wire
Step 1 (When indicating P1654-H:)
1) Turn the ignition switch OFF.
2) Lift up the fuel tank by removing the fuel tank mounting bolt.
(5-3)
3) Check the STP sensor coupler for loose or poor contacts.
If OK, then check the STP sensor lead wire continuity.
4) Disconnect the STP sensor coupler.
5) Check the continuity between R wire A and Bl/Y wire B.
If the sound is not heard from the tester, the circuit condition
is OK.
(+ R – - Ground)
(+ R – - B/Br)
FI SYSTEM DIAGNOSIS 4-57
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1
1
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