B2461: Aux Heater Flame Sensor Circuit Open
Diagnostic trouble code B2461 indicates an open circuit in the auxiliary heater flame sensor. This fault is detected when the auxiliary heater control module does not receive the expected electrical signal from the flame sensor, interrupting combustion monitoring. The flame sensor confirms that the burner has ignited properly. An open circuit prevents the module from verifying flame presence, causing the system to shut down the auxiliary heater as a safety measure to prevent fuel injection without ignition.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty or defective auxiliary heater flame sensor
- Open circuit (broken wire) in the sensor wiring harness
- Corroded, bent, or loose pins in the sensor electrical connector
- Blown fuse in the auxiliary heater system
- Internal failure of the auxiliary heater control module (HVAC)
3. Symptoms You Will Notice
- Auxiliary heater inoperative or not producing heat
- Check engine light or service heater light illuminated
4. Step-by-Step Diagnosis
Scan for codes and verify B2461 is present
Visually inspect the flame sensor connector and wiring for damage, corrosion, or breaks
Check the auxiliary heater system fuse and replace if blown
Test the flame sensor resistance and compare to specifications; replace if out of range
If wiring and sensor are good, suspect a faulty control module and perform further module diagnostics
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive, but the auxiliary heater will not operate. In cold climates, this may affect cabin comfort and defrosting capability.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on the cause. A flame sensor replacement may cost $50–$150 for parts plus labor, while control module replacement can be more expensive.