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Chevrolet B1A1B

NA-085 or 25-NA-183 please update the radio it should correct the issue, if

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Chevrolet dealer or qualified service facility to verify the stored-code combination, vehicle eligibility, and applicable GM Service Information procedure.
Confidence95%

Quick answer

For certain Chevrolet vehicles, B1A1B.00 appears in GM/NHTSA manufacturer communications related to radio diagnostics. Where B1A1B.00 is set with the specified companion codes and the vehicle is eligible for software in 25-NA-085 or 25-NA-183, the bulletin says to update the radio; it should correct the issue. Applicability and eligibility must be confirmed by a Chevrolet dealer or qualified service facility.

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 B1A1B mean?

For certain Chevrolet vehicles, B1A1B.00 appears in GM/NHTSA manufacturer communications related to radio diagnostics. Where B1A1B.00 is set with the specified companion codes and the vehicle is eligible for software in 25-NA-085 or 25-NA-183, the bulletin says to update the radio; it should correct the issue. Applicability and eligibility must be confirmed by a Chevrolet dealer or qualified service facility.

2. Technical explanation

Verified NHTSA-posted GM communications PIT6393C through PIT6393L identify B1A1B.00 among diagnostic trouble codes associated with radio-related service information. The bulletins state that when B1A1F.00, B1A1B.00, U1516, and U164E are set, and the vehicle can receive software listed in 25-NA-085 or 25-NA-183, updating the radio should correct the issue. Earlier cited revisions list a subset of these companion codes. The supplied evidence does not establish a standalone definition for B1A1B, nor does it establish that a radio update is appropriate when B1A1B occurs alone.

3. What system is affected?

Radio, based on the cited GM manufacturer communications.

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 radio software-related condition is addressed by the cited GM communications when the specified DTC combination and software eligibility criteria are met.
  • The cause of B1A1B.00 by itself 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

  • Record all stored DTCs, including whether B1A1F.00, U1516, or U164E are also present.
  • Arrange diagnosis with a Chevrolet dealer or qualified service facility.
  • Ask the service facility to check whether the vehicle is eligible for the radio software identified in 25-NA-085 or 25-NA-183.

10. Step-by-step troubleshooting

  1. Confirm the exact DTC suffix; the cited communications reference B1A1B.00.
  2. Check for the companion DTCs identified in the latest supplied PIT6393 evidence: B1A1F.00, U1516, and U164E.
  3. Have the vehicle's eligibility for the software listed in 25-NA-085 or 25-NA-183 verified.
  4. Follow GM Service Information diagnostics. The supplied bulletins state that if SI diagnostics instruct radio replacement, proceed under the applicable service procedure.

11. When to contact service

Contact a Chevrolet dealer or qualified service facility to verify the stored-code combination, vehicle eligibility, and applicable GM Service Information procedure.

12. What the service center may check

  • Verify B1A1B.00 and any companion codes.
  • Determine whether the vehicle is listed in or eligible for 25-NA-085 or 25-NA-183 software.
  • Perform the applicable radio software update when the bulletin criteria are met.
  • Use GM Service Information diagnostics if the bulletin criteria are not met or if diagnostics direct further action.

13. Possible repair or resolution

  • For qualifying vehicles with the specified DTC condition, update the radio with software listed in 25-NA-085 or 25-NA-183; the bulletin states this should correct the issue.
  • If GM Service Information diagnostics instruct radio replacement, follow the applicable service procedure. The supplied evidence does not establish when replacement is required beyond that instruction.

14. Affected vehicles

15. Related TSBs / service bulletins

  • PIT6393L, NHTSA manufacturer communication MC-11032781-0001, published May 14, 2026.
  • PIT6393K, NHTSA manufacturer communication MC-11032554-0001, published April 28, 2026.
  • PIT6393J, NHTSA manufacturer communication MC-11029962-0001, published March 6, 2026.
  • PIT6393H, NHTSA manufacturer communication MC-11026861-0001, published December 23, 2025.
  • PIT6393F, NHTSA manufacturer communication MC-11024704-0001, published October 23, 2025.
  • PIT6393E, NHTSA manufacturer communication MC-11024438-0001, published October 4, 2025.
  • PIT6393D, NHTSA manufacturer communication MC-11023907-0001, published October 1, 2025.
  • PIT6393C, NHTSA manufacturer communication MC-11023342-0001, published September 15, 2025.
  • PIT6457B, NHTSA manufacturer communication MC-11027686-0001, published January 12, 2026; the supplied summary lists B1A1B among radio-related DTC keywords.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official source: NHTSA-hosted GM manufacturer communications, including PIT6393L: https://static.nhtsa.gov/odi/tsbs/2026/MC-11032781-0001.pdf

19. Frequently asked questions

What does B1A1B mean?

The supplied verified evidence does not provide a standalone definition. It identifies B1A1B.00 as a DTC addressed in radio-related GM manufacturer communications.

Will a radio update fix B1A1B?

The cited bulletins say a radio update should correct the issue only when the specified DTC combination is present and the vehicle can receive software listed in 25-NA-085 or 25-NA-183. A fix for B1A1B.00 alone is not established by the supplied evidence.

Which vehicles are included?

Supplied applicability data identifies US Chevrolet Blazer, Bolt EV, Bolt EUV, and Equinox vehicles for model years 2023–2026. The supplied evidence does not establish that every vehicle in those ranges qualifies for the bulletin procedure; eligibility must be verified.

Is this a recall?

Not yet established by verified evidence.

20. Sources & verification

Verified
Chevrolet B1A1B: NA-085 or 25-NA-183 please update the radio it should… | EV Diagnostics