What Does B0073 Mean?
This code indicates the Body Control Module (BCM) or Restraint Control Module (RCM) has detected a fault in the deployment control circuit for the second row left seatbelt pretensioner. The subfault designation suggests an electrical issue in the pretensioner circuit, such as abnormal resistance, voltage, or continuity problems that prevent proper deployment control. This is a safety-critical system that tensions the seatbelt during a collision to reduce occupant movement.
Safety Warning
The vehicle is technically drivable, but the second row left seatbelt pretensioner will not function in a collision, significantly reducing occupant protection. This is a critical safety system failure that should be repaired immediately, especially if passengers regularly occupy that seating position.
Common Causes
35%
Damaged or corroded wiring harness connector at the pretensioner or under the seat, often from moisture intrusion or seat movement
30%
Faulty seatbelt pretensioner unit with internal circuit failure or damaged deployment squib
20%
Open or short circuit in the wiring between the RCM/BCM and the pretensioner due to seat movement or pinched wires
10%
Faulty Restraint Control Module (RCM) or Body Control Module with pretensioner driver circuit failure
5%
Poor ground connection at the pretensioner or RCM/BCM ground point
Diagnostic Steps
1
Step 1: Perform a visual inspection of the second row left seatbelt pretensioner connector under the seat for corrosion, bent pins, water intrusion, or loose connections. Check for proper seating and locking of the connector.
2
Step 2: Using a digital multimeter, measure the resistance across the pretensioner deployment squib terminals (typically 2-5 ohms for most systems). Compare readings to manufacturer specifications. Disconnect the pretensioner connector and RCM/BCM before testing to avoid accidental deployment.
3
Step 3: Inspect the wiring harness from the pretensioner to the RCM/BCM for chafing, cuts, pinches, or damage from seat track movement. Pay special attention to areas where the harness flexes or passes through metal brackets.
4
Step 4: Check for proper voltage supply (typically battery voltage) and ground at the pretensioner connector using a multimeter with the ignition on. Verify continuity of both signal and ground circuits back to the RCM/BCM.
5
Step 5: If all wiring and connections test normal, perform a resistance test on the pretensioner deployment circuit at the RCM/BCM connector to verify internal module function. Compare to manufacturer specifications (typically 2-5 ohms).
6
Step 6: After repairs, clear the code using the diagnostic tool, perform a self-test of the restraint system if available, and road test the vehicle to verify the fault does not return. Verify the airbag/seatbelt warning light is extinguished.
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) or Restraint Control Module (RCM) has detected a fault in the deployment control circuit for the second row left seatbelt pretensioner. The subfault designation suggests an electrical issue in the pretensioner circuit, such as abnormal resistance, vo...
The most common cause of B0073 (Second Row Left Seatbelt Pretensioner Deployment Control (Subfault)) is: Damaged or corroded wiring harness connector at the pretensioner or under the seat, often from moisture intrusion or seat movement
Typical repair costs for B0073 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is technically drivable, but the second row left seatbelt pretensioner will not function in a collision, significantly reducing occupant protection. This is a critical safety system failure that should be repaired immediately, especially if passengers regularly occupy that seating position.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B0073 to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS) / Occupant Safety System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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