Suzuki Boulevard M50, Service Manual, Page: 194 / 454

FI SYSTEM 5-37
“C14” (P0120-H/L) TP SENSOR CIRCUIT MALFUNCTION
INSPECTION
Step 1 (When indicating C14:)
1) Remove the fuel tank. (

6-3)
2) Turn the ignition switch OFF.
3) Check the TP sensor coupler for loose or poor contacts.
If OK, then measure the TP sensor input voltage.
4) Disconnect the TP sensor coupler.
5) Turn the ignition switch ON.
6) Measure the voltage at the Red wire
B
and ground.
7) Also, measure the voltage at the Red wire
B
and B/Br wire
C
.

TP sensor input voltage: 4.5 – 5.5 V
(
+
Red –
-
Ground)
(
+
Red –
-
B/Br)

09900-25008: Multi-circuit tester set
09900-25009: Needle pointed probe set

Tester knob indication: Voltage (

)
Is the voltage OK?
DETECTED CONDITION POSSIBLE CAUSE
C14 Output voltage is not within the following
range.
Difference between actual throttle open-
ing and opening calculated by ECM is
larger than specified value.
0.1 V
Sensor voltage < 4.8 V
• TP sensor maladjusted
• TP sensor circuit open or short
• TP sensor malfunction
• ECM malfunction
P0120
H
Sensor voltage is higher than specified
value. • TP sensor circuit shorted to VCC or ground circuit
open
• TP sensor circuit open or shorted to ground or
VCC circuit open
L
Sensor voltage is lower than specified
value.
YES Go to Step 2.
NO
• Loose or poor contacts on the ECM coupler
(terminal
6
or
D
)
• Open or short circuit in the Red wire or B/Br
wire
TP sensor ECM
E2
VCC
TP
R
Bl/B
B/Br
Bl
Y
B
1
1
V
SA
MP
LE