The Throttle Position Sensor (TPS) is mounted on the throttle body and detects the opening angle of the throttle plate. The TPS has a variable resistor (potentiometer) whose characteristic is the resistance changing according to the throttle angle. During acceleration, the TPS resistance between the reference 5V and the signal terminal decreases and output voltage increases; during deceleration, the TPS resistance increases and TPS output voltage decreases. The PCM supplies a reference 5V to the TPS and the output voltage increases directly with the opening of the throttle valve. The PCM determines operating conditions such as idle (closed throttle), part load, acceleration/deceleration, and wide-open throttle from the TPS. Also The PCM uses the Mass Air Flow Sensor (MAFS) signal along with the TPS signal to adjust fuel injection duration and ignition timing.
PCM sets DTC P0123 if the PCM detects signal voltage higher than the possible range of a properly operating TPS
Item
Detecting Condition
Possible Cause
DTC Strategy
Voltage range check
Open in signal or ground circuit
Short to battery in signal circuit
Poor connection or damaged harness
Faulty TP sensor
Enable Conditions
6V < Battery voltage <16V
Threshold Value
Voltage > 4.86 V
Diagnostic Time
1 sec.
Mil On Condition
2 Driving Cycles
Closed throttle status
Wide open throttle
Throttle opening angle(°)
0 ~ 0.5 °
Approx. 86 °
Voltage (V)
0.20 ~ 0.47 V
4.2 ~ 4.7 V
Resistance (?)
Terminal 1 & 2
0.71 ~ 1.38 ?
2.7 ?
Terminal 2 & 3
1.6 ~ 2.4 ?
Test Condition
GDS Parameter
GDS Screen
TPS VOLTAGE
Normal value with ignition "ON" & engine "OFF"
Accelerator pedal released
0.20~0.47V
Fig.1
Normal value with engine ON & accelerator pedal fully depressed
4.2~4.7V
-
Abnormal value with ignition "ON" & engine "OFF"
Power circuit open
0.01V
Fig. 2
Ground circuit open
4.99V
Fig. 3
TPS signal circuit
open
Fig. 4
short to ground
Approx. 0V
short to battery
Above 4.99V
Fig.1) Signal increases proportionally with throttle open and close angle
Fig.2) Normal value with IG "ON"
Fig.3) Open in signal or ground circuit : Approx. 5V