What Does B00C4 Mean?
This code indicates a malfunction in the passenger seat occupant classification sensor circuit 'E', which is part of the supplemental restraint system (SRS/airbag). The body control module (BCM) or airbag control module detected an internal fault or subfault condition within one of the multiple sensor elements in the occupant classification system. This sensor determines passenger weight and position to control airbag deployment force and status.
Safety Warning
This is a safety-critical fault that may cause improper airbag deployment or prevent passenger airbag from deploying correctly in a collision. The airbag warning light will be illuminated and the passenger airbag may be disabled. Do not transport passengers in the affected seat until repaired, and prioritize immediate professional diagnosis.
Common Causes
45%
Faulty occupant classification sensor mat or pressure sensor embedded in passenger seat cushion
30%
Damaged or corroded wiring harness connector at seat base or under-seat connector
15%
Water intrusion or moisture contamination in sensor mat or electrical connections
10%
Faulty airbag control module or internal processing fault in occupant detection system
Diagnostic Steps
1
Step 1: Perform visual inspection of passenger seat for physical damage, tears in upholstery, or signs of liquid spills that may have contaminated sensor mat. Check for aftermarket seat covers or objects that may interfere with sensor operation
2
Step 2: Remove passenger seat access panel or move seat fully forward to access under-seat wiring harness. Inspect all connectors for corrosion, bent pins, moisture, or loose connections. Disconnect and reconnect occupant classification sensor connector to ensure proper seating
3
Step 3: Using a digital multimeter, measure resistance values across occupant classification sensor terminals with seat empty according to manufacturer specifications (typically 200-2000 ohms depending on sensor type). Compare readings to known-good values
4
Step 4: With scan tool in live data mode, monitor occupant classification sensor voltage and status outputs while applying controlled pressure to different areas of passenger seat. Verify sensor responds appropriately to weight changes (0-5V signal typical)
5
Step 5: Check for TSBs or software updates related to occupant classification system for the specific vehicle. Perform airbag control module reprogramming if available and applicable
6
Step 6: If all wiring and connections test normal, replace occupant classification sensor mat assembly and perform airbag system calibration procedure. Clear codes and verify airbag warning light extinguishes and proper system operation
Estimated Repair Cost
$250 - $1,200
Parts + labor, varies by vehicle and location
This code indicates a malfunction in the passenger seat occupant classification sensor circuit 'E', which is part of the supplemental restraint system (SRS/airbag). The body control module (BCM) or airbag control module detected an internal fault or subfault condition within one of the multiple sens...
The most common cause of B00C4 (Passenger Seat Occupant Classification Sensor "E" (Subfault)) is: Faulty occupant classification sensor mat or pressure sensor embedded in passenger seat cushion
Typical repair costs for B00C4 range from $250 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a safety-critical fault that may cause improper airbag deployment or prevent passenger airbag from deploying correctly in a collision. The airbag warning light will be illuminated and the passenger airbag may be disabled. Do not transport passengers in the affected seat until repaired, and prioritize immediate professional diagnosis.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B00C4 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.
