What it means
The heater control circuit signal for the Bank 2 Sensor 3 heated oxygen sensor is below the expected range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The heater circuit warms the Bank 2 Sensor 3 oxygen sensor, at the third sensor position on the engine's second bank where fitted. P0063 sets when the control module detects a heater-control signal below its expected range, which can result from a short to ground, high-resistance connection, or damaged wiring.
Common causes
Most likely first.
- Heater wiring shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light on
- Oxygen-sensor heater may warm slowly
- Fuel economy may decrease
- Emissions may increase
How to diagnose it
- Record freeze-frame data and check for related heater codes to see whether the low signal is confined to Bank 2 Sensor 3.
- Verify the sensor layout and inspect Bank 2 Sensor 3 wiring for chafing, melted insulation, corrosion, or a loose connector.
- Check heater-circuit supply and ground at the connector using the wiring diagram, looking for excessive voltage drop or a short to ground.
- Disconnect the sensor and test the heater element and harness for continuity or an unintended ground, following the manufacturer's procedure.
- If the sensor and wiring pass, test the heater control circuit at the module using the manufacturer's diagnostic procedure.
Common fixes
- Repair a heater wire shorted to ground or chafed through its insulation.
- Clean or repair corroded, loose, or high-resistance Bank 2 Sensor 3 connector terminals.
- Replace the sensor if its heater element fails the manufacturer's test.
- Repair a confirmed heater-control circuit fault.
Can I keep driving?
If the engine runs normally, the car is generally driveable, but the Bank 2 Sensor 3 heater may not warm the sensor promptly and emissions can increase. Get it checked if drivability deteriorates.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.