What it means
The heater control circuit signal for the Bank 2 Sensor 3 heated oxygen sensor is above 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. P0064 sets when the control module sees a heater-control signal above its expected range, which may indicate a short to battery voltage or a damaged connection.
Common causes
Most likely first.
- Heater wiring shorted to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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 high signal affects only Bank 2 Sensor 3.
- Verify the vehicle's sensor layout and inspect the sensor connector and heat-exposed wiring for pin damage, chafing, or contact with a B+ wire.
- Using the wiring diagram, check the heater circuit for an unintended connection to battery voltage and inspect connector terminals for corrosion.
- Disconnect the sensor and test the heater element and harness as directed by the manufacturer's procedure.
- If the sensor and wiring pass, check the heater control circuit and module output using the manufacturer's diagnostic procedure.
Common fixes
- Repair wiring that is pinched against a B+ source or shorted to battery voltage.
- Clean or repair damaged or corroded 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?
The vehicle is generally driveable if it runs normally, but emissions may increase while the Bank 2 Sensor 3 heater is not operating as intended. Avoid putting off diagnosis if the engine begins running poorly.
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.