What Does B2454 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an open circuit in the auxiliary heater blower fan motor circuit. An open circuit means there is a break in the electrical path preventing current flow to the blower motor, which could be caused by damaged wiring, a faulty connector, a blown fuse, or a failed blower motor. The auxiliary heater system, often found in diesel vehicles or vehicles with supplemental heating systems, is unable to circulate heated air into the cabin.
Common Causes
35%
Open or damaged wiring harness, corroded or loose connector terminals in the auxiliary heater blower circuit
30%
Failed auxiliary heater blower motor with open internal windings or seized bearings causing circuit protection
20%
Blown fuse or faulty relay supplying power to the auxiliary heater blower motor circuit
10%
Faulty Body Control Module (BCM) with internal circuit failure or failed output driver
5%
Poor ground connection or open ground circuit for the auxiliary heater blower motor
Diagnostic Steps
1
Step 1: Perform a visual inspection of the auxiliary heater blower motor and its wiring harness for obvious damage, disconnected connectors, corrosion, or burnt wires. Check the location of the auxiliary heater unit (typically under vehicle or in engine bay).
2
Step 2: Locate and inspect the fuse and relay for the auxiliary heater blower circuit in the fuse box. Test the fuse with a multimeter for continuity and verify the relay clicks and has proper voltage output (typically 12V) when activated.
3
Step 3: Disconnect the auxiliary heater blower motor connector and use a multimeter to check for battery voltage (12V) at the power supply wire when the system is commanded on. Also verify ground circuit continuity (less than 1 ohm resistance to chassis ground).
4
Step 4: If power and ground are present at the connector, remove the blower motor and test it directly by applying 12V power and ground. If the motor does not operate, replace it. If it operates, inspect the connector pins for corrosion or damage.
5
Step 5: If no power is reaching the blower motor connector, trace the wiring harness back toward the BCM checking for breaks, shorts to ground, or damaged sections using a multimeter continuity test.
6
Step 6: After repairs, clear the code, operate the auxiliary heater system through multiple cycles, and verify the blower operates correctly and the code does not return.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an open circuit in the auxiliary heater blower fan motor circuit. An open circuit means there is a break in the electrical path preventing current flow to the blower motor, which could be caused by damaged wiring,...
The most common cause of B2454 (Aux Heater Blower Fan Circuit Open) is: Open or damaged wiring harness, corroded or loose connector terminals in the auxiliary heater blower circuit
Typical repair costs for B2454 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or drivability and the vehicle is safe to drive. The only impact is reduced cabin heating performance, particularly during cold weather operation when the auxiliary heater would normally supplement the main heating system.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2454 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Auxiliary Climate Control / Supplemental Heating System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
