What Does B0077 Mean?
This code indicates the Body Control Module (BCM) has detected a fault in the deployment control circuit for the third row center seat seatbelt pretensioner system. The pretensioner is designed to tighten the seatbelt in a collision, and this subfault suggests an electrical issue preventing proper deployment command or monitoring. The BCM continuously monitors the pretensioner circuit for proper resistance, voltage, and continuity to ensure it can function during a crash event.
Safety Warning
This is a critical safety system fault that compromises occupant protection in a collision. The third row center seatbelt pretensioner will not function properly during a crash, increasing injury risk. Repair should be completed immediately, and the affected seating position should not be used until repaired.
Common Causes
35%
Faulty pretensioner squib or internal pretensioner circuit failure
30%
Damaged, corroded, or loose wiring and connectors in the pretensioner circuit
20%
High resistance or open circuit in pretensioner wiring due to damaged harness under seat
10%
Body Control Module or SRS control module internal fault
5%
Pretensioner previously deployed and not replaced after collision
Diagnostic Steps
1
Step 1: Perform visual inspection of third row center seatbelt pretensioner assembly for physical damage, deployment indicators, or signs of previous collision. Check for red deployment indicator visible on pretensioner housing.
2
Step 2: Inspect pretensioner connector under third row center seat for corrosion, bent pins, moisture intrusion, or loose connection. Clean and secure connector if necessary.
3
Step 3: Using a multimeter, measure resistance across pretensioner squib terminals (connector disconnected, ignition off). Typical resistance should be 2-3 ohms; consult manufacturer specifications. Out-of-range readings indicate faulty pretensioner.
4
Step 4: Check continuity and resistance of wiring harness from BCM/SRS module to pretensioner connector. Look for opens, shorts to ground, or shorts to power. Inspect harness routing under seats for damage from seat track movement.
5
Step 5: Using scan tool, monitor live data for pretensioner circuit voltage and resistance values while wiggling harness connections. Fluctuating values indicate intermittent wiring fault.
6
Step 6: If all wiring and pretensioner test within specifications, suspect BCM or SRS control module fault. Verify proper ground connections to control modules and check module connectors for corrosion before considering module replacement.
Estimated Repair Cost
$400 - $1,200
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a fault in the deployment control circuit for the third row center seat seatbelt pretensioner system. The pretensioner is designed to tighten the seatbelt in a collision, and this subfault suggests an electrical issue preventing proper d...
The most common cause of B0077 (Third Row Center Seatbelt Pretensioner Deployment Control (Subfault)) is: Faulty pretensioner squib or internal pretensioner circuit failure
Typical repair costs for B0077 range from $400 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a critical safety system fault that compromises occupant protection in a collision. The third row center seatbelt pretensioner will not function properly during a crash, increasing injury risk. Repair should be completed immediately, and the affected seating position should not be used until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B0077 to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS) / Passive Safety System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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