Suzuki GA413 Service Manual page 825

DTC P0121 THROTTLE POSITION CIRCUIT RANGE/PERFORMANCE
PROBLEM
WIRING DIAGRAM – Refer to DTC P0120 section.
CIRCUIT DESCRIPTION
DTC DETECTING CONDITION
D After engine warmed up.
D Difference between actual throttle opening (detected from TP sensor)
and opening calculated by ECM (Obtained on the basis of engine
speed and intake manifold pressure) in larger than specified value.
: 2 driving cycle detection logic, continuous monitoring
DTC CONFIRMATION PROCEDURE
WARNING:
D When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
D Road test should be carried out with 2 persons, a driver and a tester, on a level road.
1) Turn ignition switch OFF. Clear DTC with ignition switch ON, check vehicle and environmental condition for:
– Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
– Ambient temp.: –10_C, 14_F or higher
– Intake air temp.: 70_C, 158_F or lower
– Engine coolant temp.: 705C, 1585F or higher
2) Warm up engine to normal operating temperature.
3) Increase vehicle speed to 30 – 40 mph, 50 – 60 km/h in 3rd gear and hold throttle valve at that opening position
for 1 min.
4) Stop vehicle.
5) Check DTC in "DTC" mode and pending DTC in "PENDING DTC" mode.
INSPECTION
STEP
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Check TP Sensor and Its Circuit.
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.
See Fig. 1.
3 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, then measure resistance between terminals and
check if each measured value is as specified below.
See Fig. 2.
Between 1 and 2: 2.5 – 6.0 kW
Between 1 and 3: 0.02 W – 6.0 kW, varying according to
Are measured values as specified?
ACTION
throttle valve opening.
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-49
POSSIBLE CAUSE
D TP sensor malfunction
D High resistance in the circuit
D ECM malfunction
YES
Go to Step 2.
If OK, substitute a
known-good ECM
and recheck.
High resistance in
"LT GRN/RED",
"GRY/YEL" or
"BLU/YEL" circuit.
If wire and
connection are
OK, substitute a
known-good ECM
and recheck.
NO
Go to "ENGINE
DIAG. FLOW
TABLE".
Go to Step 3.
Replace TP
sensor.