2015 Chevrolet Sonic
Mileage
109,071
Service Date
1/24/2023
Services Performed
- P0420 catalyst efficiency – monitored upstream and downstream o2 sensors. Found the upstream is slightly erratic. Downstream sensor had readings of 1.8v when cold, then when warm, it returned to normal range of 0-780mV. The catalyst might be inefficient, but the downstream sensor readings are unreliable. This will need the downstream sensor replaced as step 1. Then the system will be able to better montior the catalyst. There is an odor of raw exhaust under hood so the manifold converter may have a leak anyway.Recommend replacement of downstream o2 sensor as first step
Claudia O. gave our service a 5 star review on 1/27/2023
