What Does P0064 Mean?
The ECM has detected a high voltage or excessive current condition in the heater control circuit for the heated oxygen sensor (HO2S) at Bank 2, Sensor 3. This typically indicates a short to battery voltage in the heater control wire, an internally shorted heater element, or an ECM driver that is stuck on. The excessive current flow can damage the ECM driver circuit or blow the heater fuse. The driver will see the check engine light.
Common Causes
32%
Short to battery voltage in the heater control wire
30%
Internally shorted O2 sensor heater element (low resistance)
18%
Wiring harness chafed against power wire or metal component
12%
ECM heater driver circuit stuck in the ON state
8%
Water intrusion in the connector causing a low-resistance path
Diagnostic Steps
1
Disconnect the Bank 2 Sensor 3 connector and measure heater element resistance. A very low reading (under 2 ohms) indicates an internally shorted heater that's drawing excessive current.
2
With the sensor disconnected, measure voltage on the ECM control (ground) wire at the sensor connector with key on. Any voltage above 1V indicates a short to power in the harness.
3
Inspect the wiring harness routing from the ECM to the sensor. Look for chafing against hot exhaust components, sharp metal edges, or where the harness crosses other high-current wires.
4
Check for moisture in the O2 sensor connector — water between the pins creates a low-resistance path that the ECM interprets as high current. Dry and apply dielectric grease.
5
If wiring and sensor test normally, monitor the ECM control wire with an oscilloscope while commanding the heater circuit. The ECM should be duty-cycling the ground — a constant ground indicates a stuck driver.
Estimated Repair Cost
$80 - $400
Parts + labor, varies by vehicle and location
The ECM has detected a high voltage or excessive current condition in the heater control circuit for the heated oxygen sensor (HO2S) at Bank 2, Sensor 3. This typically indicates a short to battery voltage in the heater control wire, an internally shorted heater element, or an ECM driver that is stu...
The most common cause of P0064 (HO2S Heater Control Circuit High (Bank 2, Sensor 3)) is: Short to battery voltage in the heater control wire
Typical repair costs for P0064 range from $80 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive, but the excessive current condition could blow the O2 heater fuse (potentially affecting other O2 sensors on the same circuit) or damage the ECM heater driver over time. Repair within 2 weeks to prevent secondary damage. No immediate safety hazard.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0064 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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