What Does B1844 Mean?
This code indicates the Body Control Module (BCM) has detected a malfunction in the vehicle's integrated hands-free phone handset circuit. The BCM monitors the electrical circuit that powers and communicates with the phone handset module, and has identified an open circuit, short circuit, or component failure. This is a manufacturer-specific body code that affects the vehicle's communication and convenience systems.
Common Causes
40%
Faulty or corroded phone handset module or internal circuit board failure
30%
Damaged, chafed, or corroded wiring harness between BCM and phone handset
20%
Loose or corroded electrical connector at phone handset or BCM interface
10%
Failed Body Control Module unable to properly communicate with handset circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of phone handset module mounting location and check for physical damage, loose mounting, or signs of moisture intrusion
2
Step 2: Disconnect phone handset connector and inspect connector pins for corrosion, bent pins, or terminal tension issues; clean with electrical contact cleaner if necessary
3
Step 3: Using a digital multimeter, check for power and ground at the handset connector with ignition on; verify voltage matches manufacturer specifications (typically 12V on power pin and less than 0.5V on ground)
4
Step 4: Test continuity of all wiring between phone handset connector and BCM connector, checking for opens or shorts to ground or power in each circuit
5
Step 5: If wiring and power supply are confirmed good, substitute with a known-good phone handset module to verify if original unit is faulty
6
Step 6: Clear codes, cycle ignition, and verify repair by testing phone handset functionality and confirming no code returns
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a malfunction in the vehicle's integrated hands-free phone handset circuit. The BCM monitors the electrical circuit that powers and communicates with the phone handset module, and has identified an open circuit, short circuit, or compone...
The most common cause of B1844 (Phone Handset Circuit Failure) is: Faulty or corroded phone handset module or internal circuit board failure
Typical repair costs for B1844 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 continue driving. This is a convenience feature failure that only affects hands-free phone functionality and should be repaired at your earliest convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1844 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Communication Systems
Difficulty
Type
Manufacturer
Recommended Tools
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