P1199 Possible Causes
- Faulty O2 sensor
- O2 sensor harness is open or shorted
- Poor electrical connection in the O2 sensor circuit
How to Fix Code P1199?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon warning light)
P1199 Meaning
Oxygen sensors (O2S) or heated oxygen sensors (HO2S) must reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches this temperature, the sooner the sensor will start sending an accurate signal to the Engine Control Module (ECM).
To achieve the required temperature, a heating element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor’s heating element based on signals from engine coolant temperature and engine load. The ECM controls the heater circuit by allowing current to flow to ground.
The ECM monitors the voltage signal received through the heater circuit and determines the circuit’s status by comparing the detected voltage to factory specifications.