What Does P0063 Mean?
The ECM has detected a low voltage or low current condition in the heater control circuit for the heated oxygen sensor (HO2S) at Bank 2, Sensor 3. This typically indicates an open circuit, excessively high resistance, or a short to ground in the heater supply wiring. The O2 sensor heater cannot draw enough current to warm the sensor element. The driver will see the check engine light but is unlikely to notice drivability issues.
Common Causes
35%
Open circuit in the O2 sensor heater (burned-out heater element)
28%
Open or high-resistance wiring in the heater supply or ground circuit
18%
Blown O2 heater fuse
12%
Corroded or disconnected O2 sensor connector
7%
ECM internal heater driver open circuit
Diagnostic Steps
1
Check the O2 sensor heater fuse first — this is the most common cause of a low-circuit code. If blown, inspect for the root cause (shorted sensor or wiring) before replacing.
2
Disconnect the Bank 2 Sensor 3 connector and measure heater resistance. An open circuit (OL/infinite) reading confirms a burned-out heater element requiring sensor replacement.
3
If the sensor heater resistance is within spec (2-15 ohms typically), measure voltage at the sensor connector with key on. No voltage on the supply wire means an open between the fuse box and sensor.
4
Perform a voltage drop test on the heater supply and ground wires under load. Connect a test light across the heater pins at the sensor connector — if it doesn't illuminate, trace the open circuit from the fuse to the connector.
5
Check for corroded or backed-out pins in the O2 sensor connector. Even slight pin recession can prevent contact and create an open circuit.
Estimated Repair Cost
$80 - $300
Parts + labor, varies by vehicle and location
The ECM has detected a low voltage or low current condition in the heater control circuit for the heated oxygen sensor (HO2S) at Bank 2, Sensor 3. This typically indicates an open circuit, excessively high resistance, or a short to ground in the heater supply wiring. The O2 sensor heater cannot draw...
The most common cause of P0063 (HO2S Heater Control Circuit Low (Bank 2, Sensor 3)) is: Open circuit in the O2 sensor heater (burned-out heater element)
Typical repair costs for P0063 range from $80 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive indefinitely. This affects only the heater warmup speed for a downstream monitoring sensor. Engine performance is unaffected. Will cause a failed emissions test. Low priority repair.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0063 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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