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Mazda U2120

00 or/and U2500:82 are stored and i-ACTIVSENSE warning light (amber) turns on after the reprogramming, refer to SA-043/20. • If the Welcome Lamp function is accidently activated wh

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Mazda dealer or qualified Mazda service facility. Provide the stored code(s), the amber i-ACTIVSENSE warning status, and whether the concern began after ECU reprogramming.
Confidence95%

Quick answer

For listed U.S. Mazda vehicles, verified manufacturer communications identify U2120:00 as a DTC that may be stored after ECU reprogramming together with U2500:82 and an amber i-ACTIVSENSE warning light. Mazda directs technicians to SA-043/20 in that situation.

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 U2120 mean?

For listed U.S. Mazda vehicles, verified manufacturer communications identify U2120:00 as a DTC that may be stored after ECU reprogramming together with U2500:82 and an amber i-ACTIVSENSE warning light. Mazda directs technicians to SA-043/20 in that situation.

2. Technical explanation

The supplied official Mazda/NHTSA communications state that, after reprogramming, DTC U2120:00 and/or U2500:82 may be stored and the amber i-ACTIVSENSE warning light may illuminate. The communications direct service personnel to refer to SA-043/20. They also state that DTCs should be cleared after repair work is complete. One communication notes that accidental activation of the Welcome Lamp function while using MDARS may cause this concern and directs technicians to check and correct it as necessary under SA-054/20.

3. What system is affected?

i-ACTIVSENSE warning indication is specifically identified. The underlying system fault meaning is not yet established by verified evidence.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • DTC U2120:00 may be stored after ECU reprogramming.
  • DTC U2500:82 may also be stored.
  • The amber i-ACTIVSENSE warning light may turn on after reprogramming.

6. Possible causes

  • Post-reprogramming condition involving U2120:00 and/or U2500:82, as described in Mazda manufacturer communications.
  • Accidental activation of the Welcome Lamp function while using MDARS may cause this concern, according to one supplied manufacturer communication.

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

  • Do not attempt high-voltage diagnosis or repair.
  • Record whether the amber i-ACTIVSENSE warning light appeared after ECU programming.
  • Arrange Mazda dealer or qualified service diagnosis, particularly if the code and warning appeared after reprogramming.

10. Step-by-step troubleshooting

  1. A Mazda technician should follow the applicable manufacturer procedure and refer to SA-043/20 when U2120:00 and/or U2500:82 are stored with the amber i-ACTIVSENSE warning light after reprogramming.
  2. The supplied communications state that DTCs should be cleared after all repair work is complete.
  3. Where applicable, Mazda service information states that accidental Welcome Lamp activation while using MDARS should be checked and corrected as necessary, with reference to SA-054/20.

11. When to contact service

Contact a Mazda dealer or qualified Mazda service facility. Provide the stored code(s), the amber i-ACTIVSENSE warning status, and whether the concern began after ECU reprogramming.

12. What the service center may check

  • Confirm whether U2120:00 and/or U2500:82 are stored after ECU reprogramming.
  • Confirm whether the amber i-ACTIVSENSE warning light is illuminated.
  • Refer to Mazda service information SA-043/20 for the documented post-reprogramming condition.
  • If applicable, check for accidental Welcome Lamp activation during MDARS use, following SA-054/20.
  • Clear DTCs after all repair work is complete, as specified in the supplied communications.

13. Possible repair or resolution

  • The exact repair resolution is not yet established by verified evidence.
  • The verified communications direct service personnel to SA-043/20 for U2120:00 and/or U2500:82 with an amber i-ACTIVSENSE warning after reprogramming.
  • For the documented MDARS/Welcome Lamp condition, the communication directs technicians to check and correct as necessary under SA-054/20.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Mazda/NHTSA Manufacturer Communication 09-003-25, published January 15, 2025: identifies U2120:00 and/or U2500:82 with amber i-ACTIVSENSE warning after reprogramming; directs reference to SA-043/20.
  • Mazda/NHTSA Manufacturer Communication 09-020-24, published March 26, 2024: identifies U2120:00 and/or U2500:82 with amber i-ACTIVSENSE warning after any ECU is programmed; directs reference to SA-043/20.
  • Mazda/NHTSA Manufacturer Communication 09-024-23, published June 12, 2023: identifies the same post-reprogramming condition; also mentions possible accidental Welcome Lamp activation during MDARS use and refers to SA-054/20.

16. Recall information

  • No recall is established by the supplied verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Mazda manufacturer communications: https://static.nhtsa.gov/odi/tsbs/2025/MC-11013657-0001.pdf ; https://static.nhtsa.gov/odi/tsbs/2024/MC-10252505-0001.pdf ; https://static.nhtsa.gov/odi/tsbs/2023/MC-10238670-0001.pdf

19. Frequently asked questions

What does U2120 mean here?

The supplied evidence specifically documents U2120:00 as a code that may be stored after ECU reprogramming, possibly with U2500:82 and an amber i-ACTIVSENSE warning light. A broader technical definition is not yet established by verified evidence.

Is U2120 linked to the amber i-ACTIVSENSE warning light?

Yes, the supplied Mazda communications specifically describe U2120:00 and/or U2500:82 stored with the amber i-ACTIVSENSE warning light on after reprogramming.

Can I drive or charge the vehicle?

Driving and charging safety are not yet established by verified evidence.

Which vehicles are included in the supplied applicability data?

U.S.-market Mazda CX-90 model years 2022–2024 and Mazda MX-30 model years 2022–2024 are listed. The supplied applicability records contain overlapping MX-30 year ranges.

20. Sources & verification

Verified
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