P0061 HO2S Heater Resistance, Row 2, Sensor 3

What is the P0061 code?

The P0061 error code is a generic powertrain-related code. It indicates that the Powertrain Control Module (PCM) has detected an abnormal resistance in the heater circuit of oxygen sensor (lambda sensor) #3, located downstream of the catalytic converter on bank 2 (the engine side that does not contain cylinder #1). This fault prevents the sensor from reaching its operating temperature quickly, disrupting proper engine operation, especially when cold.

Symptoms and Severity of the Fault

This code is considered serious and should not be ignored. Common symptoms include:

• ❄️ Hard starting in cold weather
• ⛽ Engine overheating or excessive fuel consumption
• ⚫ Black smoke from the exhaust (rich fuel mixture)
• ⚠️ Illumination of the Malfunction Indicator Lamp (MIL)
• 📟 Possible appearance of other related fault codes

Possible Causes of the P0061 Code

Several components can be the source of this problem:

• 🔌 Damaged, loose, or corroded wiring
• 🛠️ Faulty O2 sensor (heater element failure)
• ⚡ Blown fuse or faulty relay
• 🔋 Ground or power supply voltage issue

Diagnosis and Solutions

Before any intervention, consult your manufacturer’s Technical Service Bulletins (TSBs) to check if the problem is known and subject to a recall or specific procedure.

Recommended Diagnostic Steps:

1. Visual Inspection: Check the condition of the wires and connectors, especially near hot parts (exhaust) or sharp edges.
2. Fuse Check: Test the relevant fuses and relays with a multimeter, under load to avoid false positives.
3. Using an OBD2 Scanner: Read the fault codes and live data. Observe the heater circuit voltage of the sensor when the engine is cold. It should be close to the battery voltage.
4. Resistance Test: Using a multimeter, measure the resistance of the lambda sensor’s heating element (refer to the manufacturer’s specific values). Remember to disconnect the connectors before any measurement.

Common Repairs:

• Replace the faulty oxygen sensor (this is often the solution)
• Repair or replace the damaged wiring harness
• Replace a blown fuse or faulty relay

Important Tip: After repair, clear the codes and perform a drive cycle so the PCM can recalibrate the values and turn off the MIL.

Conclusion

The P0061 code indicates a serious problem with your lambda sensor’s heater circuit. Accurate diagnosis helps avoid unnecessary part replacement. If you are not comfortable with these procedures, consult a professional mechanic for a reliable diagnosis.