Suzuki 2000 Grand Vitara SQ625 Service Manual page 58

6-54 ENGINE DIAGNOSIS (G16 / J20 ENGINES)
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start en-
gine.
3) Increase vehicle speed to 60 km/h (40 mph).
4) Keep driving above vehicle speed for 5 min. (Change of vehicle speed is permitted in this step).
5) Stop vehicle and run engine at idle speed for 1 min.
6) Increase vehicle speed till engine speed is reached 2,000 – 3,000 r/min in proper gear.
7) Keep driving at that engine speed for 30 sec. or more (Engine speed is kept constant in this step).
8) Stop vehicle.
9) Repeat step 6) to 8).
10) Check DTC and pending DTC by using scan tool.
TROUBLESHOOTING (DTC P0121)
STEP
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Is there a DTC related to TP sensor (DTC P0122 and
P0123)?
3 Check TP Sensor and its Circuit.
When using SUZUKI scan tool:
1) Turn ignition switch OFF and connect SUZUKI
scan tool to DLC.
2) Turn ignition switch ON and check TP sensor output
voltage when throttle valve is at idle position and fully
opened.
When not using SUZUKI scan tool:
1) Turn ignition switch ON.
2) Check voltage at terminal C51-3-9 of ECM connector
connected, when throttle valve is at idle position and
fully opened.
Does voltage vary within specified value linearly as
shown in figure?
4 Check TP Sensor.
1) Turn ignition switch OFF.
2) Disconnect TP sensor connector.
3) Check for proper connection to TP sensor at each
terminal.
4) If OK, check TP sensor for resistance referring
to "TP sensor Inspection" in Section 6E1.
Is check result satisfactory?
Fig. for Step 3
3.4 – 4.7 V
0.5 – 1.2 V
At idle position
Throttle Opening
ACTION
Fully open
YES
Go to Step 2.
Go to applicable
DTC Diag. Flow
Table.
If voltmeter was
used, check
terminal C51-3-9 for
poor connection.
If OK, substitute a
known-good ECM
(PCM) and recheck.
High resistance in
"Gr /R", "R/G" or
"Gr /Y" circuit.
If wire and
connection are OK,
substitute a known-
good ECM (PCM)
and recheck.
NO
Go to "ENGINE
DIAG. FLOW
TABLE".
Go to Step 3.
Go to Step 4.
Replace TP sensor.