What Does B0013 Mean?
This code indicates a malfunction in the passenger knee bolster airbag deployment circuit or control system. The airbag control module (ACM) has detected a subfault condition that affects the knee bolster's ability to deploy properly during a collision. This represents a safety system fault where the supplemental restraint system monitoring has identified an electrical or mechanical issue with the knee airbag deployment circuit.
Safety Warning
This is a critical safety system fault that prevents proper airbag deployment in a collision, potentially resulting in serious injury to the passenger. Vehicle should be repaired immediately by a qualified technician, and while drivable, the passenger knee airbag will not function in a crash scenario.
Common Causes
35%
Faulty knee bolster airbag inflator or internal resistance out of specification
30%
Damaged or corroded wiring harness and connectors in knee bolster airbag circuit
20%
Faulty airbag control module (ACM) with internal deployment circuit fault
10%
Poor ground connection or high resistance in airbag system ground circuit
5%
Clockspring or related SRS circuit intermittent connection affecting system monitoring
Diagnostic Steps
1
Step 1: Perform visual inspection of passenger knee bolster airbag area for physical damage, previous deployment, or visible connector damage. Check for proper installation and any signs of water intrusion or corrosion at the knee bolster connector.
2
Step 2: Disconnect battery and wait 10+ minutes for capacitor discharge. Using a digital multimeter, measure resistance across the knee bolster airbag squib terminals (typically 2-3 ohms specification). Compare readings to manufacturer specifications.
3
Step 3: Inspect airbag wiring harness from ACM to knee bolster connector for chafing, pinching, or damage. Pay special attention to areas where harness passes through firewall or under carpet. Check connector pins for corrosion, bent pins, or signs of overheating.
4
Step 4: Using a multimeter, test continuity and resistance of the deployment circuit wiring from ACM connector to knee bolster connector with harness disconnected at both ends. Verify circuit integrity and absence of short to ground or short to power.
5
Step 5: Verify proper ground connections for airbag system, typically located under dashboard or at body mounting points. Clean and tighten ground connections, then measure resistance to ensure less than 0.5 ohms.
6
Step 6: After repairs, reconnect battery and use scan tool to clear codes and perform ACM self-test function. Verify airbag warning light operates normally (illuminates then extinguishes) and no codes return. Document all resistance readings and repair actions.
Estimated Repair Cost
$200 - $1,500
Parts + labor, varies by vehicle and location
This code indicates a malfunction in the passenger knee bolster airbag deployment circuit or control system. The airbag control module (ACM) has detected a subfault condition that affects the knee bolster's ability to deploy properly during a collision. This represents a safety system fault where th...
The most common cause of B0013 (Passenger Knee Bolster Deployment Control (Subfault)) is: Faulty knee bolster airbag inflator or internal resistance out of specification
Typical repair costs for B0013 range from $200 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a critical safety system fault that prevents proper airbag deployment in a collision, potentially resulting in serious injury to the passenger. Vehicle should be repaired immediately by a qualified technician, and while drivable, the passenger knee airbag will not function in a crash scenario.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B0013 to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS/Airbag)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
