P1143 INFINITI Possible Causes
- Faulty heated oxygen sensor, bank 1, sensor 1
- Intake air leaks
- Open or short circuit in the heated oxygen sensor bank 1, sensor 1 harness
- Poor electrical connection in the heated oxygen sensor bank 1, sensor 1 circuit
- Fuel pressure
- Injectors
How to Fix P1143 INFINITI Code?
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.
Technical Notes
If there is no intake air leak, the most likely cause of the P1143 code is the front oxygen sensor bank 1.
When is the Code Detected?
The sensor’s maximum and minimum voltages are not reached at the specified voltages.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon Warning Light)
P1143 INFINITI Meaning
The heated oxygen sensor 1 is placed in the front pipe. It detects the amount of oxygen in the exhaust gases compared to the outside air. The heated oxygen sensor 1 has a closed-end zirconia ceramic tube. Zirconia generates a voltage from about 1 V under richer conditions to 0 V under leaner conditions. The heated oxygen sensor 1 signal is sent to the Engine Control Module (ECM). The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the steep change from 1V to 0V.