The Electronic Throttle Control(ETC) system is made of the components throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2. TPS1&2 are sharing the same source voltage and ground.The throttle valve opening is control by throttle motor which is controlled by Engine Control Module(ECM).The opposite position indicator shows inverted signal characteristics.TPS1 output voltage increases smoothly in proportion with the throttle valve opening angle after starting. TPS2 output voltage decreases in inverse proportion with the throttle valve opening angle after starting. TPS provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.
Checking output signals from TPS1 every 8.5 sec. under detecting condition, if an output signal is above 4.75V for more than 0.1 sec., ECM sets P0123. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal high
Poor connection
Open or short to battery in signal harness
Open in ground harness
TPS
ECM
Enable Conditions
IG "ON"
Threshold value
The voltage of TPS > 4.75V
Diagnosis Time
Continuous (more than 0.1 sec. failure for every 8.5 sec.test)
MIL On Condition
1 driving cycles
Throttle Opening (°)
Output Voltage (V) [Vref=5.0]
TPS1
TPS2
0°
0.0V
5.0V
10°
0.5V
4.5V
20°
0.9V
4.1V
30°
1.4V
3.6V
40°
1.8V
3.2V
50°
2.3V
2.7V
60°
70°
80°
90°
100°
110°
Fig.1) Normal data & waveform of TPS1 & TPS2 with no accel padal depressed under IG ON condition
Fig.2) Normal data & waveform of TPS1 & TPS2 with accel padal depressed under IG ON condition
Fig.3) Abnormal data of TPS1 & TPS2 at open condition