| DTC | Affected Circuit |
|---|---|
| P0135 | Heated Oxygen Sensor Heater Circuit (Bank 1, Sensor 1) |
| P0141 | Heated Oxygen Sensor Heater Circuit (Bank 1, Sensor 2) |
| P0155 | Heated Oxygen Sensor Heater Circuit (Bank 2, Sensor 1) |
| P0161 | Heated Oxygen Sensor Heater Circuit (Bank 2, Sensor 2) |
DTC IDENTIFICATION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Note. Bank No. 1 refers to bank that includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1. Sensor No. 1 refers to sensor closest to engine block. Sensor No. 2 refers to sensor furthest away from engine block.
Circuit Description
The oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. The ECM uses this input signal to determine fuel injection system operation. Sensors include heater.
If DTCs are set, ECM will operate in fail-safe mode (faulty heater circuit is turned off). DTCs are set when oxygen sensor heater current draw more than 2 amps. DTCs are also set when oxygen sensor heater current draw is .20 amp or less. Possible causes are
- Heated oxygen sensor.