Code Definition
- DTC P0141: Heated Oxygen Sensor Heater Circuit (Bank No. 1, Sensor No. 2)
- DTC P0161: Heated Oxygen Sensor Heater Circuit (Bank No. 2, Sensor No. 2)
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. Bank 1 is also known as right bank (RH). Heated oxygen sensor No. 1 refers to sensor closest to engine block. Heated oxygen sensor No. 2 refers to sensor farthest from engine block.
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
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.
Diagnostic Aids
Using scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.