Invalid Data from Sunroof Control Module
The U046A code indicates that a receiving control module (typically the BCM, gateway, or overhead module) has detected invalid, inconsistent, or out-of-range data from the Sunroof Control Module over the CAN or LIN bus. While physical communication is present, the data integrity—such as checksum, rolling counter, or logical values—has failed.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty Sunroof Control Module or corrupted firmware
- Damaged wiring or connectors on the CAN/LIN data bus (open, short to ground/battery, or high resistance)
- Power or ground supply issues to the sunroof module (low voltage, voltage spikes)
- Electromagnetic interference (EMI) on the communication bus
- Software mismatch or loss of programming after module replacement or update
3. Symptoms You Will Notice
- Sunroof may not operate or operates erratically
- Check Engine Light or other warning lights illuminated
- Related features (e.g., interior lights, rain sensor) may malfunction
4. Step-by-Step Diagnosis
Scan all modules for related codes and check communication status
Inspect sunroof module power, ground, and bus wiring for damage or corrosion
Test bus resistance and signal integrity with an oscilloscope
Attempt to reprogram or update the sunroof module software
Replace the sunroof module if all else fails
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive, but the sunroof may not function properly. Have the issue diagnosed soon to prevent potential electrical problems.
How much does it cost to fix?▼
Diagnosis typically costs $100–$150. Repair costs vary: wiring repairs $150–$300, module replacement $300–$800 including labor.