2003 Mitsubishi Eclipse O2 Sensor Fault Codes P0135 and P0141 Location & Diagnosis
I'm experiencing trouble codes P0135 (Oxygen Sensor Heater Circuit Bank 1 Sensor 1) and P0141 (Oxygen Sensor Heater Circuit Bank 2 Sensor 2) on my 2003 Mitsubishi Eclipse. While I understand these are related to oxygen sensor heater circuits, I'm unsure of the exact locations of these sensors. As both codes appear simultaneously, I'm wondering if it's due to wiring issues—such as a short or damaged wire—or whether a complete replacement of the sensors is necessary. My vehicle has been consuming excessive fuel, which is becoming increasingly concerning. Any detailed information about where these oxygen sensors are located in the exhaust system would be greatly appreciated. Additionally, I'd like to know if it's common for both sensors to fail at once or if one failure typically precedes the other. Thanks in advance for any help—this car has been putting a real strain on my budget and patience!
The oxygen sensors in your 2003 Mitsubishi Eclipse are located in the exhaust system: one is positioned just before the catalytic converter (Bank 1, Sensor 1), and the other is located after the catalytic converter (Bank 2, Sensor 2). It's highly unlikely that both sensors would fail simultaneously—this suggests a wiring or connector issue rather than sensor failure. Please check all relevant fuses, as well as the wiring harnesses and connectors leading to each oxygen sensor. Corrosion or loose connections can trigger these error codes. Once you've inspected those components, consider testing with a scan tool to verify if the fault persists. Good luck—feel free to update us on your progress.