What Does B2455 Mean?
This code indicates that the Body Control Module (BCM) has detected a fault in the auxiliary heater blower motor circuit or component. The auxiliary heater is a supplemental heating system, often used in diesel vehicles or cold climates to provide additional cabin heat. The BCM has identified an electrical fault, mechanical failure, or performance issue with the blower motor that prevents proper operation.
Common Causes
40%
Auxiliary heater blower motor failure due to worn brushes, seized bearings, or internal short circuit
30%
Damaged wiring harness, corroded connectors, or loose connections between BCM and auxiliary heater blower motor
20%
Faulty auxiliary heater blower motor relay or blown fuse in the blower circuit
10%
Failed Body Control Module (BCM) or internal driver circuit malfunction
Diagnostic Steps
1
Step 1: Perform visual inspection of auxiliary heater blower motor, wiring harness, and connectors for obvious damage, corrosion, loose connections, or burnt terminals. Check all related fuses and relays for integrity.
2
Step 2: Using a digital multimeter, test power and ground supply at the auxiliary heater blower motor connector with ignition on and heater activated. Expect battery voltage (12-14V) on power wire and less than 0.5V on ground. Check for voltage drop exceeding 0.2V indicating poor connections.
3
Step 3: Disconnect blower motor connector and measure motor resistance across terminals. Typical resistance should be 1-5 ohms for functional motor. Infinite resistance indicates open circuit; near-zero indicates short circuit. Also test for continuity to ground (should be open).
4
Step 4: Apply direct battery voltage to blower motor terminals (bypassing vehicle harness) to verify motor operation. If motor runs normally, fault is in wiring or control circuit. If motor fails to operate or runs abnormally, replace blower motor.
5
Step 5: If motor and power supply are good, use scan tool to activate auxiliary heater blower motor via BCM active tests/output controls. Monitor actual vs commanded operation to determine if BCM driver circuit is functioning properly.
6
Step 6: After repair, clear codes, perform full system functional test by operating auxiliary heater through all speed ranges, and road test vehicle to verify proper operation and confirm no code recurrence.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a fault in the auxiliary heater blower motor circuit or component. The auxiliary heater is a supplemental heating system, often used in diesel vehicles or cold climates to provide additional cabin heat. The BCM has identified an ele...
The most common cause of B2455 (Aux Heater Blower Faulted) is: Auxiliary heater blower motor failure due to worn brushes, seized bearings, or internal short circuit
Typical repair costs for B2455 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive as this affects only the auxiliary heating system, not primary vehicle operation. Repair is recommended before cold weather to maintain cabin comfort, but poses no immediate safety risk to vehicle operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2455 to identify the root cause.
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Quick Info
Category
Body
System
Auxiliary Climate Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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