Suzuki GSF650A Service Manual page 160

1A-85 Engine General Information and Diagnosis:
Step
3 1) Connect the ECM coupler. Refer to "ECM Removal and
Installation in Section 1C (Page 1C-1)".
2) Disconnect the STP sensor coupler.
3) Turn the ignition switch ON.
4) Measure the input voltage at the R wire and ground.
Also, measure the input voltage at the R wire and B/Br
wire.
Special tool
(A): 09900–25008 (Multi-circuit tester set)
Tester knob indication
Voltage ( )
STP sensor input voltage
4.5 – 5.5 V
((+) terminal: R – (–) terminal: Ground, (+) terminal: R
– (–) terminal: B/Br)
Is the voltage OK?
Action
(A)
I718H1110197-02
Yes
Go to Step 4.
No
Open or short circuit in
the R or B/Br wire.