1997 Dodge Stratus P0140 P0141 P0455 Codes - O2 Sensor and Post-Cat Issue at 110,000 Miles
A friend owns a 1997 Dodge Stratus with approximately 110,000 miles, equipped with a 2.4L 16-valve engine and automatic transmission. The check engine light comes on intermittently. While the P0455 code is not a major concern, the presence of P0140 and P0141 codes suggests an issue with the oxygen (O2) sensor. These codes specifically point to Bank 1 Sensor 2, which is located after the catalytic converter (post-cat). The P0140 indicates a faulty heater circuit in the sensor, while P0141 points to slow or no response from the same sensor. Together, these codes strongly suggest either a failing O2 sensor or wiring faults such as open or short circuits. Given the vehicle's high mileage, it is important to inspect for corrosion, loose connections, or damaged wiring harnesses near the exhaust system. Any insights on diagnosing this issue would be greatly appreciated.
In a 1997 Dodge Stratus with only two sensors, Bank 1 Sensor 2 is located downstream of the catalytic converter. This is the most likely source of both P0140 and P0145 codes.