What Does B2584 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the child seat detection system, typically an occupant classification sensor or pressure mat located in the front passenger seat. The system uses sensors to determine if a child seat is present and adjusts airbag deployment accordingly. An open circuit means the BCM cannot receive signal from the sensor, preventing proper airbag system operation for passenger side.
Common Causes
40%
Damaged or disconnected wiring harness under passenger seat, often caused by seat movement, cleaning, or items pushed under seat
30%
Faulty child seat detection sensor/mat or occupant classification sensor built into passenger seat cushion
20%
Corroded or loose electrical connector at sensor or BCM connection point
10%
Failed Body Control Module (BCM) internal circuit for child seat detection input
Diagnostic Steps
1
Step 1: Perform visual inspection under front passenger seat for disconnected, damaged, or pinched wiring harness and connectors. Check for proper seating of all connectors and visible signs of damage or corrosion
2
Step 2: Using a digital multimeter, test continuity through the child seat detection sensor circuit from the sensor connector to the BCM connector with ignition off. Expected reading should be within specification (typically 100-500 ohms depending on vehicle, check service manual)
3
Step 3: Inspect the occupant classification sensor mat by carefully removing passenger seat bottom cushion. Look for physical damage, tears, or liquid intrusion in the sensor mat
4
Step 4: If wiring shows continuity and sensor appears intact, check voltage supply to sensor with ignition on (typically 5V reference). If no voltage present, trace circuit back to BCM
5
Step 5: If all circuits test properly, suspect faulty sensor mat or BCM. Replace sensor mat first as it is more common failure point, then clear codes and test system
6
Step 6: After repair, perform final verification by cycling ignition, clearing codes, and verifying passenger airbag indicator lamp functions correctly with weight on seat
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the child seat detection system, typically an occupant classification sensor or pressure mat located in the front passenger seat. The system uses sensors to determine if a child seat is present and adjusts airbag deplo...
The most common cause of B2584 (Child Seat Detection Circuit Open) is: Damaged or disconnected wiring harness under passenger seat, often caused by seat movement, cleaning, or items pushed under seat
Typical repair costs for B2584 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is drivable but passenger airbag system may not function correctly, potentially deploying when it shouldn't with a child seat present or failing to deploy when needed. Repair should be completed promptly as this affects critical safety system functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2584 to identify the root cause.
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Quick Info
Category
Body
System
Occupant Safety System (Airbag/SRS)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
