Chevrolet U1126
- Do not replace the front camera. - Diagnose the CAN Bus 8 issue using SI 5199684
Quick answer
For applicable Chevrolet Blazer and Equinox vehicles, U1126 is addressed in GM bulletin PIT6503/PIT6503A/PIT6503B as a possible CAN Bus 8 loss-of-communication DTC. If CAN Bus 8 is affected broadly, the bulletin says not to replace the B174W Front View Camera module; diagnose the CAN Bus 8 issue using SI 5199684.
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1. What does U1126 mean?
For applicable Chevrolet Blazer and Equinox vehicles, U1126 is addressed in GM bulletin PIT6503/PIT6503A/PIT6503B as a possible CAN Bus 8 loss-of-communication DTC. If CAN Bus 8 is affected broadly, the bulletin says not to replace the B174W Front View Camera module; diagnose the CAN Bus 8 issue using SI 5199684.
2. Technical explanation
The verified manufacturer communication directs technicians to check whether the K56 Serial Data Gateway Module is also setting loss-of-communication DTCs for other electronic control units on CAN Bus 8. U1126 is listed as an example alongside U1127, U0235, and U1616. Where the entire bus is impacted, the verified instruction is to diagnose the CAN Bus 8 issue using SI 5199684 rather than replacing the front camera.
3. What system is affected?
CAN Bus 8 communication network; K56 Serial Data Gateway Module and, in the bulletin context, the B174W Front View Camera module.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
Not yet established by verified evidence.
6. Possible causes
- A CAN Bus 8 issue, if the entire bus is impacted, is established by the manufacturer communication as the diagnostic direction. A specific underlying fault cause is not yet established by verified evidence.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Arrange diagnosis by a qualified Chevrolet/GM service provider.
- Provide the service provider with DTC U1126 and reference PIT6503, PIT6503A, or PIT6503B and SI 5199684.
- Do not assume the B174W Front View Camera module requires replacement when the entire CAN Bus 8 network is affected.
10. Step-by-step troubleshooting
- Check whether the K56 Serial Data Gateway Module is also setting loss-of-communication DTCs against other ECUs on CAN Bus 8.
- If the entire CAN Bus 8 network is impacted, diagnose the CAN Bus 8 issue using SI 5199684.
- Do not replace the B174W Front View Camera module when the entire bus is impacted.
11. When to contact service
Service is recommended for network diagnosis. The verified communications direct diagnosis through SI 5199684 when CAN Bus 8 is broadly impacted.
12. What the service center may check
- Check K56 Serial Data Gateway Module fault information for loss-of-communication DTCs involving other CAN Bus 8 ECUs.
- Determine whether the entire CAN Bus 8 network is impacted.
- Follow SI 5199684 for CAN Bus 8 diagnosis when applicable.
13. Possible repair or resolution
- Do not replace the B174W Front View Camera module solely because the entire CAN Bus 8 network is impacted.
- Diagnose the CAN Bus 8 issue using SI 5199684. The specific repair outcome is not yet established by verified evidence.
14. Affected vehicles
- Chevrolet Blazer · 2024–2026 · US
- Chevrolet Equinox · 2024–2026 · US
- Chevrolet Equinox · 2025–2026 · US
15. Related TSBs / service bulletins
- PIT6503B, published June 17, 2026: Chevrolet communication directing CAN Bus 8 diagnosis and stating not to replace the B174W Front View Camera module if the entire bus is impacted. Source: https://static.nhtsa.gov/odi/tsbs/2026/MC-11034014-0001.pdf
- PIT6503A, published June 3, 2026: Chevrolet communication directing CAN Bus 8 diagnosis through SI 5199684 and stating not to replace the front camera if the entire bus is impacted. Source: https://static.nhtsa.gov/odi/tsbs/2026/MC-11033726-0001.pdf
- PIT6503, published April 14, 2026: Chevrolet communication directing CAN Bus 8 diagnosis through SI 5199684 and stating not to replace the front camera if the entire bus is impacted. Source: https://static.nhtsa.gov/odi/tsbs/2026/MC-11031514-0001.pdf
16. Recall information
No recall relationship is established by verified evidence.
17. Official manufacturer information
Verified official manufacturer communications are available through NHTSA: PIT6503B (https://static.nhtsa.gov/odi/tsbs/2026/MC-11034014-0001.pdf), PIT6503A (https://static.nhtsa.gov/odi/tsbs/2026/MC-11033726-0001.pdf), and PIT6503 (https://static.nhtsa.gov/odi/tsbs/2026/MC-11031514-0001.pdf).
19. Frequently asked questions
Should the front camera be replaced for U1126?
Not if the entire CAN Bus 8 network is impacted. PIT6503-series communications specifically say not to replace the B174W Front View Camera module and instead diagnose CAN Bus 8 using SI 5199684.
What should a technician check with U1126?
The verified communication directs checking whether the K56 Serial Data Gateway Module is also setting loss-of-communication DTCs against other ECUs on CAN Bus 8.
Is U1126 safe to drive or charge with?
Not yet established by verified evidence.
Which vehicles are covered by the provided applicability evidence?
Chevrolet Blazer model years 2024 through 2026 in the United States, and Chevrolet Equinox model years 2024 through 2026 in the United States. The supplied data also separately lists 2025 through 2026 Equinox coverage.