U0471: Invalid Data from Restraint Sensor A
The U0471 code indicates that a vehicle control module (typically the engine or body control module) has received invalid, corrupt, or unprocessable data from the Restraints System Sensor A. This sensor is part of the Supplemental Restraint System (SRS), commonly known as the airbag system. Communication occurs over the CAN (Controller Area Network) data bus. The fault does not necessarily mean the sensor is defective; rather, the transmitted data does not meet the expected format or values, which can be due to interference, bus communication failures, or issues within the restraint system module.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty Restraints System Sensor A (SRS sensor)
- Damaged or corroded wiring or connectors on the CAN bus between the sensor and control module
- Faulty Restraints Control Module (Sensing and Diagnostic Module - SDM)
- Electromagnetic interference on the communication line
- Abnormal CAN bus resistance (too high or too low)
- Outdated or corrupt control module software
- Grounding issues in the restraint system module
3. Symptoms You Will Notice
- Airbag warning light illuminated on the dashboard
- Possible SRS system malfunction or deactivation
- No other drivability issues typically present
4. Step-by-Step Diagnosis
Scan the vehicle with a professional OBD2 scanner to confirm U0471 and check for related codes.
Inspect the Restraints System Sensor A and its wiring/connectors for damage, corrosion, or loose connections.
Check the CAN bus wiring and termination resistors for proper resistance (typically 60 ohms between CAN-H and CAN-L).
Test the Restraints Control Module (SDM) for proper operation and update software if needed.
Clear the code and test drive to see if it returns; if it does, further diagnosis of the sensor or module is required.
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive. The U0471 code indicates a fault in the airbag system, which may prevent the airbags from deploying in a crash. Have the vehicle inspected immediately.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. A simple wiring repair may cost $100-$200, while replacing a sensor or SDM module can range from $300 to $1,000 or more, including labor.