What does vehicle fault code P0064 mean?
The P0064 fault code, applicable to all car manufacturers, means “HO2S Heater Control Circuit High (Bank 2, Sensor 3)“.
Background information: The oxygen sensor measures the oxygen content in the engine exhaust to correct the fuel injection quantity, thereby achieving the optimal air-fuel ratio for the engine. In OBD fault codes, you will often see the oxygen sensor number specified. Bank 1 refers to the bank containing cylinder 1, and the remaining bank is Bank 2. Regardless of the bank, the first sensor always refers to the upstream oxygen sensor (before the catalytic converter), and the second sensor always refers to the downstream oxygen sensor (after the catalytic converter). The electronic control unit (ECU) maintains the oxygen sensor temperature at 780°C by controlling the on/off state of the oxygen sensor heater. This fault code will appear if the voltage in the heater control circuit is higher than the calibrated maximum value.
Symptoms of Error Code P0064
- Engine malfunction light illuminated
- Increased fuel consumption
- Unstable engine idling
- Difficulty starting the engine in cold weather
- Poor dynamics
Causes of Error Code P0064
- Open wires or connectors in the sensor circuit
- Damaged oxygen sensor
- Short circuit to ground or power supply
- Electronic control unit (ECU) malfunction
Error Code P0064 in Different Vehicles
Toyota’s P0064: This error is usually caused by the failure of the second-row sensors after 100,000 kilometers.
Ford’s P0064: The problem may be unreliable contacts in the fuse box.
Subaru’s P0064: Often occurs in winter due to corrosion of the exhaust system connectors.
Hyundai’s P0064: The most common cause is damage to the sensor heater due to vibration.
BMW’s P0064: This error may be caused by a malfunction in the engine control system.
How to diagnose Error Code P0064?
- Using an OBD2 scanner to read error codes
- Visually inspect the B2S3 sensor connectors and wiring.
- Check the resistance of the oxygen sensor heating element.
- Measure the voltage in the heater circuit.
- Check the relays, fuses, and power supply.
Possible Causes and Diagnostic Methods
| Possible Causes | How to Check？ |
|---|---|
| Damaged wiring | Visual inspection, multimeter testing |
| Sensor heater malfunction | Measure the resistance of the heating element |
| Relay/fuse problem | Power circuit test, relay test |
| ECU malfunction | Scanner diagnostics, check the power circuit |
Required tools: OBD2 scanner, multimeter, wiring diagram, sensor removal tool kit
How to resolve error code P0064? (Solutions to the Problem)
Simple Repair Methods
- Clean and reinstall the sensor connector
- Replace the blown fuse
- Reset the error code after resolving the cause
In-depth Diagnostic and Repair Solutions
- Replace the faulty oxygen sensor
- Repair or replace damaged wires
- Repair or re-flash the ECU if necessary
Troubleshooting Through Symptoms
| Symptoms | Possible Solutions |
|---|---|
| High fuel consumption | Check and replace the B2S3 sensor |
| Check if the engine starts | Diagnose and repair the heating circuit |
| Uneven engine operation | Check sensor signals and power |
P0064 Frequently Asked Questions
Can I drive with error code P0064?
Not recommended. Abnormalities in the oxygen sensor heater can lead to increased fuel consumption, environmental pollution, and unstable engine operation.
What happens if I don’t fix error P0064?
Ignoring the error can lead to decreased catalytic converter efficiency, reduced traction, and increased engine wear.
Is it possible to reset the P0064 code without fixing it?
For example, you can disconnect the battery terminals or use a scanner. However, if the cause isn’t addressed, the error will reappear, and the problem will persist.
Does the P0064 error only occur in winter?
No, but it’s more likely to occur in winter due to higher humidity, contact corrosion, and increased load on the sensor heating system.
Do I need to replace the oxygen sensor to trigger a P0064 error?
Only if it’s truly defective. Sometimes simply repairing the wiring or replacing the fuse is sufficient.
Related OBD2 Errors for P0064:
P0036 – HO2S Heater Control Circuit (Bank 1, Sensor 2)
P0054 – HO2S Heater Resistance (Bank 1, Sensor 2)
P0141 – O2 Sensor Heater Circuit (Bank 1, Sensor 2)
Important! Errors may not immediately affect vehicle behavior, but if left unattended, they can lead to further wear on components and violations of environmental standards. Don’t delay diagnosing and fixing errors. This will help prevent serious malfunctions and reduce future fuel and repair costs.