Yamaha 4TX-AE1, Service Manual

Page: 320 / 332

8-44
Revolution
(
10
3
r / min)
Tachometer display
Engine speed
time
(seconds)
TPS (THROTTLE POSITION SENSOR) SELF DIAGNOSIS
ELEC
1
2
3
NOTE:
TPS (THROTTLE POSITION SENSOR) SELF DIAGNOSIS
CIRCUIT DIAGRAM If the needle of the tachometer shows the follow-
ing pattern while the engine is running, the throttle
position sensor circuit is broken, shorted, or the
TPS (throttle position sensor) is locked. In that
case, it would be best to inspect it.
0 rpm – 3 seconds
3,000 rpm – 2.5 seconds
present engine revolutions – 3 seconds
The above pattern is repeated.
The needle of the tachometer keeps pointing to
“0” rpm for 6 seconds when the engine is not run-
ning.
If any trouble occurs in the TPS, the ignition tim-
ing signal transmitted from the TPS to the ignitor
unit is limited to the full-open state signal.
11
TPS (throttle position sensor)
12
Ignitor unit