Circuit Description

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. DTC is set when heated oxygen sensor heater current draw exceeds 2.35 amps, or heated oxygen sensor heater current draw is .20 amp or less when heater operates. ECM will operate in fail-safe mode if DTC P0141 is set. Possible causes are:

• Heated oxygen sensor No. 2 heater circuit is open or shorted.
• Defective heated oxygen sensor No. 2 heater.
• Defective ECM.