What Does B004B Mean?
This code indicates a fault in the third row right frontal airbag deployment circuit, specifically affecting the Stage 3 deployment control. The Airbag Control Module (ACM) has detected an electrical or communication subfault that prevents proper control of the multi-stage airbag deployment system for the third row right passenger position. This compromises the supplemental restraint system's ability to deploy the airbag at the appropriate force level during a collision event.
Safety Warning
This is a critical safety issue that requires immediate attention and should be repaired before regular vehicle operation. The third row right frontal airbag may not deploy properly or at all during a collision, significantly increasing injury risk to occupants in that seating position. The vehicle should only be driven to a repair facility.
Common Causes
35%
Faulty third row right frontal airbag module or internal squib resistance out of specification
30%
Damaged, corroded, or loose airbag connector at the airbag module or along the harness
25%
Open or short circuit in the airbag deployment wiring harness between ACM and third row airbag
10%
Faulty Airbag Control Module (ACM) internal Stage 3 deployment driver circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of third row right frontal airbag and yellow safety connector for physical damage, corrosion, or loose connections. Check for proper seating and locking of connector terminals.
2
Step 2: With battery disconnected and waiting 10+ minutes for capacitor discharge, disconnect the third row right airbag connector and measure squib resistance across airbag terminals using a digital multimeter (expected range typically 2-3 ohms, consult vehicle-specific specification).
3
Step 3: Measure continuity and resistance of airbag deployment circuit wiring from ACM connector to airbag connector (both wires) with airbag disconnected. Check for opens (infinite resistance), shorts to ground, or shorts to power (should show only wire resistance, typically less than 5 ohms).
4
Step 4: Inspect wiring harness routing through third row seat mounting points, hinges, and floor areas for pinched, chafed, or damaged wires that may cause intermittent faults.
5
Step 5: If all wiring and airbag resistance values are within specification, suspect ACM internal fault. Clear codes and perform test drive to verify if code returns, which would indicate ACM replacement is necessary.
6
Step 6: After repairs, clear codes, perform ACM system self-test or initialization procedure, and verify airbag warning light extinguishes and no codes return.
Estimated Repair Cost
$300 - $1,800
Parts + labor, varies by vehicle and location
This code indicates a fault in the third row right frontal airbag deployment circuit, specifically affecting the Stage 3 deployment control. The Airbag Control Module (ACM) has detected an electrical or communication subfault that prevents proper control of the multi-stage airbag deployment system f...
The most common cause of B004B (Third Row Right Frontal Stage 3 Deployment Control (Subfault)) is: Faulty third row right frontal airbag module or internal squib resistance out of specification
Typical repair costs for B004B range from $300 to $1,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a critical safety issue that requires immediate attention and should be repaired before regular vehicle operation. The third row right frontal airbag may not deploy properly or at all during a collision, significantly increasing injury risk to occupants in that seating position. The vehicle should only be driven to a repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B004B to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS) / Airbag System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
