Symptoms Of A Bad Oxygen Sensor
The effects of a bad oxygen sensor can be very subtle since they usually do not cause serious drive-ability problems. Here are the most common symptoms:
- The check engine light (CEL) will be illuminated on your instrument cluster.
- The diagnostic trouble codes lighting up the CEL usually are:
- P0131 Upstream Heated Oxygen Sensor (O2S11) Circuit Out Of Range Low Voltage (Bank 1).
- P0133 Upstream Heated Oxygen Sensor (O2S11) Circuit Slow Response (Bank 1).
- Really bad gas mileage.
- Won't pass state mandated emission testing.
More Test Articles
I've written quite a few 1.9L, 2.0L 'how to' tutorials that may help you troubleshoot the issues on your Ford Escort, Mercury Tracer or Ford Focus. You can find the complete list at:
Here's a sample of the Ford 1.9L, 2.0L articles you'll find:
- Crankshaft Position (CKP) Sensor Test.
- How To Test Engine Compression.
- Ignition Coil Pack Test (this info is found at: easyautodiagnostics.com).
If this info saved the day, buy me a beer!