Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensor includes a heater. DTC is set when heated oxygen sensor No. 1 does not output a rich condition once engine is at normal operating temperature, engine speed is more than 1400 RPM and vehicle speed is 25-62 MPH for at least 2 minutes.
Possible causes are:
Fuel system malfunction.
Defective fuel injector.
Ignition system malfunction.
Exhaust system leak.
Heated oxygen sensor No. 1 circuit is open or shorted.
Defective heated oxygen sensor No. 1.
Vehicle run out of fuel.
Only testings would tell you what is wrong.
Tuesday, June 11th, 2013 AT 12:24 PM