HO2S Heater Resistance (Bank 2, Sensor 3)
Code P0061 indicates the upstream oxygen sensor heater circuit on Bank 2 Sensor 3 is not functioning properly. The heater element inside the O2 sensor fails to warm up quickly during cold starts, preventing accurate fuel mixture readings until the sensor reaches operating temperature.
What You Might Notice
- Delayed engine startup or longer cranking time
- Diminished fuel efficiency
- Black smoke from exhaust during cold starts
- Rich fuel mixture condition during warm-up
- Check Engine Light illuminated
Most Common Causes
- 1
Faulty O2 Sensor Heater Element
The heating element inside the oxygen sensor has failed or burned out, preventing the sensor from reaching operating temperature quickly enough for proper readings.
- 2
Broken or Disconnected Wiring
Wiring harness to the oxygen sensor heater circuit is damaged, corroded, or completely disconnected, interrupting power to the heater element.
- 3
Faulty Connector or Terminals
The connector pins are corroded, loose, or damaged, preventing proper electrical contact to the heater circuit.
- 4
Engine Control Module Issue
A failure in the ECM's oxygen sensor heater control circuit or relay prevents power delivery to the sensor heater.
How to Diagnose It
- 1
Check Faulty O2 Sensor Heater Element — The heating element inside the oxygen sensor has failed or burned out, preventing the sensor from reaching operating temperature quickly enough for proper readings.
- 2
Check Broken or Disconnected Wiring — Wiring harness to the oxygen sensor heater circuit is damaged, corroded, or completely disconnected, interrupting power to the heater element.
- 3
Check Faulty Connector or Terminals — The connector pins are corroded, loose, or damaged, preventing proper electrical contact to the heater circuit.
- 4
Check Engine Control Module Issue — A failure in the ECM's oxygen sensor heater control circuit or relay prevents power delivery to the sensor heater.
How to Fix It
- 1
Replace O2 Sensor
Remove the faulty Bank 2 Sensor 3 oxygen sensor and install a new OEM or quality replacement sensor with functioning heater element.
- 2
Repair or Replace Wiring Harness
Inspect the wiring harness connecting to the oxygen sensor heater for breaks, burns, or corrosion. Repair damaged sections or replace the entire harness if necessary.
- 3
Clean or Replace Connector
Disconnect the oxygen sensor connector and clean corrosion from the terminals using electrical contact cleaner and a wire brush. Replace the connector if pins are damaged or won't maintain contact.
- 4
Test ECM and Heater Relay
Using a multimeter, test for voltage at the oxygen sensor heater connector when the engine is cranking. If no voltage is present, the ECM or heater relay may be faulty and require replacement.
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