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Cadillac U164B

If customer concern is related to one of the symptoms below, verify customers radio is

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact an authorized Cadillac service center if there is a related radio/customer concern or if U164B remains present. Provide the stored code and reference the applicable PIT6393 manufacturer communication.
Confidence95%

Quick answer

For applicable Cadillac EVs, U164B is addressed in GM/Cadillac radio-related service communications as a DTC that can set because of a software anomaly. The cited guidance says to ignore U164B in that context and not replace the radio for this DTC.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

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1. What does U164B mean?

For applicable Cadillac EVs, U164B is addressed in GM/Cadillac radio-related service communications as a DTC that can set because of a software anomaly. The cited guidance says to ignore U164B in that context and not replace the radio for this DTC.

2. Technical explanation

Verified NHTSA-posted manufacturer communications PIT6393C through PIT6393J list U164B among radio-related DTCs that may set due to a software anomaly. The supplied evidence explicitly instructs technicians not to replace the radio for these DTCs. The diagnostic database’s canonical wording is incomplete, so a fuller DTC definition is not established by the supplied verified evidence.

3. What system is affected?

Radio/infotainment-related system, based on the manufacturer communications.

4. How serious is this code?

Not yet established by verified evidence. The supplied manufacturer guidance identifies a software-anomaly context and advises against radio replacement for U164B in that context.

5. Symptoms you may notice

  • The supplied evidence refers to customer concerns and symptoms but does not provide the symptom list. Specific symptoms are not yet established by verified evidence.

6. Possible causes

  • A radio software anomaly is identified in the manufacturer communications as a reason U164B may set.
  • Other causes are 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

  • Record the customer concern and the presence of U164B for service diagnosis.
  • Use the applicable Cadillac service information and manufacturer communication when having the vehicle evaluated.
  • Do not assume radio replacement is required solely because U164B is stored; the cited guidance specifically advises against replacing the radio for this DTC in the described software-anomaly context.

10. Step-by-step troubleshooting

  1. Confirm vehicle applicability and review the applicable version of Cadillac/GM manufacturer communication PIT6393.
  2. Have qualified service personnel evaluate the radio software level and follow the applicable manufacturer procedure.
  3. The manufacturer communication cautions that, when a radio software update includes USB file transfer, the USB file must be handled as directed in the service procedure. Further USB-update instructions are not established by the supplied evidence.

11. When to contact service

Contact an authorized Cadillac service center if there is a related radio/customer concern or if U164B remains present. Provide the stored code and reference the applicable PIT6393 manufacturer communication.

12. What the service center may check

  • Verify whether the vehicle is within the listed Cadillac model-year applicability.
  • Check for U164B and other stored DTCs using approved diagnostic procedures.
  • Review the applicable radio software guidance in PIT6393.
  • Do not replace the radio solely for U164B when the bulletin’s software-anomaly condition applies.

13. Possible repair or resolution

  • The verified communications support software-focused diagnosis rather than radio replacement for U164B in the described context.
  • The exact final repair or software-update outcome is not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • PIT6393J, NHTSA Manufacturer Communication PDF 11029962, published March 6, 2026: Lists U164B among DTCs that can set due to a software anomaly and says not to replace the radio for these DTCs. https://static.nhtsa.gov/odi/tsbs/2026/MC-11029962-0001.pdf
  • PIT6457B, NHTSA Manufacturer Communication PDF 11027686, published January 12, 2026: Lists U164B as an additional keyword in a radio/DTC communication. https://static.nhtsa.gov/odi/tsbs/2026/MC-11027686-0001.pdf
  • PIT6393H, NHTSA Manufacturer Communication PDF 11026861, published December 23, 2025. https://static.nhtsa.gov/odi/tsbs/2025/MC-11026861-0001.pdf
  • PIT6393F, NHTSA Manufacturer Communication PDF 11024704, published October 23, 2025. https://static.nhtsa.gov/odi/tsbs/2025/MC-11024704-0001.pdf
  • PIT6393E, NHTSA Manufacturer Communication PDF 11024438, published October 4, 2025. https://static.nhtsa.gov/odi/tsbs/2025/MC-11024438-0001.pdf
  • PIT6393D, NHTSA Manufacturer Communication PDF 11023907, published October 1, 2025. https://static.nhtsa.gov/odi/tsbs/2025/MC-11023907-0001.pdf
  • PIT6393C, NHTSA Manufacturer Communication PDF 11023342, published September 15, 2025. https://static.nhtsa.gov/odi/tsbs/2025/MC-11023342-0001.pdf

16. Recall information

  • No recall information was supplied or established by the verified evidence.

17. Official manufacturer information

Verified applicability: US-market Cadillac CELESTIQ (2023–2026), LYRIQ (2023–2026), OPTIQ (2023–2026), and VISTIQ (2023–2026). Some applicability entries overlap by model year in the supplied database. Refer to the NHTSA-posted manufacturer communications listed above for official bulletin information.

19. Frequently asked questions

Does U164B mean the radio must be replaced?

No, not in the software-anomaly context described by PIT6393. The supplied manufacturer communications explicitly say not to replace the radio for U164B and the listed related DTCs.

What is the verified cause of U164B?

The verified communications state that U164B may set because of a software anomaly. Whether that applies to every occurrence is not established by the supplied evidence.

Is it safe to drive or charge with U164B?

Not yet established by verified evidence.

Which Cadillac vehicles are listed as applicable?

The supplied applicability data lists US-market 2023–2026 Cadillac CELESTIQ, LYRIQ, OPTIQ, and VISTIQ models.

20. Sources & verification

Verified
Cadillac U164B: If customer concern is related to one of the symptoms… | EV Diagnostics