Suzuki SY413 Service Manual page 2765

6-2-48 ENGINE GENERAL INFORMATION AND DIAGNOSIS (J18 ENGINE WITH WU TWC)
TROUBLESHOOTING (DTC P0120)
STEP
1 Was "ENGINE DIAG. FLOW TABLE"
performed?
2 Check TP Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition
switch OFF and then turn ignition switch
ON.
2) Check throttle valve opening percentage
displayed on scan tool while opening
throttle valve from idle position to full
open position. See Fig. 1.
Is it displayed 96% or higher or 2% or less?
3 Check Wire Harness.
1) Disconnect connector from TP sensor
with ignition switch OFF.
2) Check for proper connection to TP sensor
at "P / G", "Gr" and "Or" wire terminal.
3) If OK, then with ignition switch ON, check
voltage between each of "P / G" and "Gr"
wire terminals and "Or" wire terminal.
See Fig. 2.
Is voltage about 4 – 6 V at each terminal?
4 Check TP Sensor.
1) Check resistance between terminals of
disconnected ECM connector. See Fig. 3.
Between C20-18 and C20-27: 0.1 – 6.5 kW
(varying linearly according to throttle
valve opening)
Between C20-25 and C20-27: 4.0 W – 6.0
kW
Are measured values within specifications?
Fig.1 for Step 2
ACTION
Fig.2 for Step 3
YES
Go to Step 2.
Go to Step 3.
Go to Step 4.
Substitute a known-good
ECM and recheck.
Fig.3 for Step 4
NO
Go to "ENGINE DIAG.
FLOW TABLE".
Intermittent trouble.
Check for intermittent
referring to "Intermittent
and Poor Connection" in
Section 0A.
"P / G" wire open, "P / G"
wire shorted to ground cir-
cuit or power circuit or "Or"
wire, "Gr" wire open or
shorted to ground circuit or
poor C20-18 or C20-25
connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.
Replace TP sensor.