Auxiliary Heater Overheat Timeout
The B2467 code indicates that the auxiliary heater control module detected that the time required for the unit to reach a safe cool-down temperature after shutdown exceeded the maximum allowed limit. This typically occurs when the purge ventilation fails to dissipate residual heat quickly enough. The code is often linked to the diagnostic circuit or pin A453-5, which is associated with the temperature sensor or burner control relay. If the module does not register a temperature drop within the specified time, it stores this code to prevent system overheating.
1. Commonly Affected Makes
2. Most Common Causes
- Blocked or restricted auxiliary heater exhaust duct
- Faulty or slow-running combustion air blower (purge fan)
- Damaged or out-of-range auxiliary heater temperature sensor
- Short circuit, open circuit, or high resistance in wiring to the sensor or blower (reference A453-5)
- Faulty auxiliary heater control module (HCM)
- Excessive soot buildup in the combustion chamber
3. Symptoms You Will Notice
- Auxiliary heater may shut down prematurely or fail to start
- Reduced heating performance or no heat output
4. Step-by-Step Diagnosis
Scan for related codes and check freeze frame data
Inspect auxiliary heater exhaust for blockages or restrictions
Test the combustion air blower operation and speed
Check the temperature sensor resistance and compare to specifications
Inspect wiring and connectors at the sensor, blower, and control module (especially pin A453-5) for damage or corrosion
If all else is okay, consider replacing the auxiliary heater control module
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended, as the auxiliary heater may overheat or fail, potentially causing a fire hazard. Have the system inspected and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on the root cause. A simple sensor replacement may be on the lower end, while a control module or blower replacement can be higher.