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Step 3
1) Turn the ignition switch OFF.
2) Connect the STP sensor coupler.
3) Insert the needle pointed probes to the lead wire coupler.
4) Disconnect the STVA lead wire coupler.
5) Turn the ignition switch ON.
6) Measure the STP sensor output voltage at the coupler
(between
ffi
Yellow and 8 Black wires) by turning the sec-
ondary throttle valve (close and open) with a finger.
FI
SYSTEM
DIAGNOSIS
4-49
_ STP
sensor
output
voltage
Throttle valve is closed : Approx. 0.5 V
Throttle valve is opened: Approx. 3.7 V
,rootl
09900·25008: Multi
circuit
tester set
09900·25009: Needle pointed probe
set
~
Tester
knob
indication: Voltage
(::-:-::)
Is the voltage OK?
3
3
•
Blue, Yellow or Black wire open or shorted to
ground, or poor @ connection.
•
If wire and connection are OK, intermittent trou-
YES
ble or faulty ECM.
•
Recheck each terminal and wire harness for
open circuit and poor connection.
•
Replace the ECM with a new one, and inspect it
again.
NO
If check result is not satisfactory, replace STP
sensor with a new one.
ECM couplers