P2099 Diagnostic and Repair for 2015 Jeep Grand Cherokee 3.6L V6
Both oxygen sensors have been replaced, a tune-up was performed, and the fuel system was purged. After driving 116 miles, the check engine light reactivated with the P2099 code returning. The dealer suspects an internal engine issue, despite the vehicle currently running smoothly at 66,066 miles. Can faulty fuel injectors cause a rich condition that triggers this code? Seeking input on potential post-catalytic converter oxygen sensor circuit faults or other contributing factors.
Why is the dealer suggesting an internal engine problem? The P2099 code typically points to issues in the post-cat O2 sensor circuit. Possible causes include exhaust leaks near the catalytic converter, a faulty catalytic converter, or a defective oxygen sensor. Did you replace the rear O2 sensor with an OEM part? What are your fuel trims under various load conditions? Can you obtain a graph of the rear O2 sensor readings for further analysis?