U0477: Invalid Data from Restraint Sensor G
The U0477 code indicates that the control module (typically the Restraint Control Module or airbag module) has received invalid, corrupt, or out-of-range data from the Restraint Sensor G over the CAN bus. This sensor is part of the impact or occupant detection system. According to SAE J2012, U04XX codes denote data communication issues where the receiving module detects erroneous information from another module or sensor on the network.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Internal failure of the Restraint Sensor G
- Damaged wiring or connectors between the sensor and the control module
- Corrosion or abnormal resistance in the CAN bus communication circuits
- Failure of the Restraint Control Module (RCM, SDM, or equivalent)
- Electromagnetic interference affecting the data signal
- Outdated or corrupted module software
3. Symptoms You Will Notice
- Airbag warning light illuminated on the dashboard
- Supplemental Restraint System (SRS) fault message displayed
- Possible disabling of airbag or pretensioner systems
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data using a compatible OBD2 scanner
Inspect the Restraint Sensor G and its wiring harness for physical damage, corrosion, or loose connections
Test the CAN bus circuits for proper resistance and voltage levels
Check for technical service bulletins (TSBs) related to software updates for the RCM
If wiring and sensor are okay, suspect a faulty RCM and perform module communication tests
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive because the airbag system may be disabled, increasing injury risk in a crash. Have the vehicle towed to a repair shop.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on whether the sensor, wiring, or control module needs replacement. Diagnostic fees are extra.