P0061 – HO2S Heater Control Circuit Low (Bank 2 Sensor 3)
The P0061 diagnostic trouble code indicates that the Engine Control Module (ECM) has detected a low voltage condition in the heater control circuit of the heated oxygen sensor (HO2S) located at Bank 2 Sensor 3.
The oxygen sensor heater helps the sensor reach its operating temperature quickly after engine startup. When the ECM detects lower-than-expected voltage in the heater circuit, it stores the P0061 code and turns on the Check Engine Light.
Common Symptoms
- Check Engine Light ON
- Delayed oxygen sensor warm-up
- Slightly increased fuel consumption
- Usually no significant drivability issues
Common Causes
- Faulty heated oxygen sensor (HO2S)
- Short to ground in the heater control circuit
- Damaged wiring or connector
- Blown heater fuse
- Rarely, a faulty ECM
Basic Diagnosis
Inspect the oxygen sensor wiring and connector for damage or corrosion. Check the heater fuse, verify the power supply and ground, and test the heater element resistance using a multimeter. Replace the sensor if the heater circuit fails specification.
Diagnostic Note: Bank 2 Sensor 3 is not present on every vehicle. Sensor location, wiring colors, and circuit design vary by manufacturer and exhaust system configuration. Always refer to the factory wiring diagram before testing.