P1121 KIA Possible Causes
- Faulty throttle position sensor
- Throttle position sensor harness is open or shorted
- Poor electrical connection in throttle position sensor circuit
How to Fix P1121 KIA Code?
Start by checking the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
When is the Code Detected?
If the difference between the actual value and the calculated value exceeds the threshold value, the ECM judges it as a fault and the DTC is set.
Symptoms
Possible symptoms
Illuminated engine light (or service engine soon warning light)
P1121 KIA Meaning
The throttle position (TP) sensor measures the throttle valve opening angle and is mounted on the side of the throttle body and connected to the throttle blade shaft. The resistance of the TP sensor changes according to the throttle blade shaft position. The TP sensor has a potentiometer whose resistance changes with the throttle position. The engine control module (ECM) provides a 5-volt reference voltage to the TP sensor. The ECM reads the voltage across the TP sensor and converts it to throttle position. During acceleration, the TP sensor resistance decreases. During deceleration, the TP sensor resistance increases. The ECM uses the TP sensor signal to adjust injector timing and pulse width. The TP sensor signal along with the MAF sensor signal are used by the ECM to calculate engine load. Throttle angle information is sent to the ECM for detecting engine conditions such as idle, partial load, full load condition, and anti-shock condition and for correcting fuel enrichment during acceleration.