TGB EST 1000, Service Manual

Page: 65 / 269

4-2. FUEL INJECTION SYSTEM
4-2-27
TMAP SENSOR CIRCUIT MALFUNCTION
DETECTED CONDITION POSSIBLE CAUSE
T-MAP sensor voltage low or high
(0.1 V Sensor voltage < 4.8 V)
NOTE:
Note that atmospheric pressure varies
depending on weather conditions as well as
altitude.
Take that into consideration when inspecting
voltage.
•
Clogged vacuum passage between throttle
body and T-MAP sensor
•
Air being drawn from vacuum passage
between throttle body and T-MAP sensor
•
T-MAP sensor circuit open or shorted to
ground
•
T-MAP sensor malfunction
•
ECM malfunction
INSPECTION
Step 1
1) Loosen and lift up the fuel tank.
2) Turn the ignition switch OFF.
3) Check the T-MAP sensor couple for loose or
poor contacts.
If OK, then measure the T-MAP sensor input
voltage.
4) Disconnect the T-MAP sensor coupler.
5) Turn the ignition switch ON.
6) Measure the voltage at the Yellow/Black wire
and ground.
7) Also, measure the voltage at the
Yellow/Black wire and Gray/Red wire.
T-MAP sensor input voltage: 4.5
–
5.5 V
(+Yellow/Black
–
- Ground)
(+Yellow/Black
–
- Gray/Red)