Recent Repair – Rochester, PA
A Jeep was serviced in Rochester, PA for a check engine light with a stored P0420 (catalyst efficiency) code.
Initial inspection included reviewing live scan data and comparing upstream and downstream oxygen sensor activity. The upstream O2 sensor signal was not responding as expected and showed limited switching, which can affect how the engine control module evaluates catalyst performance.
The upstream oxygen sensor was replaced, and the system was rechecked. After the repair, the sensor signal returned to normal operation and the code did not reset during verification.
This type of condition can sometimes be related to sensor performance rather than catalytic converter failure, which is why confirming operation with scan data is an important step.
Service was completed on-site.
