Thermostat , installed between engine and radiator, is automatically opened or closed in order to control the amount of flowing water so that ECM matains engine coolant temperature at certain level. If, generally, engine coolant temperature reaches about 80℃(176 °F), wax in the thermostat is expended in order to open the valve. And, reversely, if coolant temperature is low, wax in the thermostat is contracted that makes valve is closed. Thermostat maintains engine temperature in order to active best engine performance and prevent overheat and overcooling.
If the sensor input voltage is higher than the maximum threshold value during 0.14 sec under normal driving condition, ECM sets DTC P0123.
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 > 4.63 V | |
Diagnosis Time |
•
0.14 sec | |
MIL On Condition |
•
1 driving cycles |
Fig. 1) Normal waveform of TPS1 & TPS2 with accel padal depressed under IG ON condition
