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Mazda P143B

00) is found based on the voltage down from the BPS, replace the Sub Battery following the procedures in the Workshop Manual. 1. PCM 2. BPS Unit 3. Sub Battery PHEV Refueling Proce

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Mazda dealer or qualified service provider if P143B:00 is present. The verified Mazda communication directs Sub Battery replacement according to the Workshop Manual.
Confidence95%

Quick answer

For verified Mazda PHEV applications, P143B:00 is documented when the Backup Power Supply Battery (BPS) detects low voltage from the Sub Battery. Mazda’s documented resolution is Sub Battery replacement using the Workshop Manual procedure.

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 P143B mean?

For verified Mazda PHEV applications, P143B:00 is documented when the Backup Power Supply Battery (BPS) detects low voltage from the Sub Battery. Mazda’s documented resolution is Sub Battery replacement using the Workshop Manual procedure.

2. Technical explanation

Mazda states that its PHEV models use a Sub Battery as backup power for several systems if electrical supply from the main battery is lost. The Backup Power Supply Battery (BPS) is located under the passenger-side foot support. The supplied official Mazda communications state that if a warning light/DTC P143B:00 is found based on voltage drop from the BPS, the Sub Battery is to be replaced following the Workshop Manual. The exact diagnostic system name and full DTC definition are not yet established by verified evidence.

3. What system is affected?

Backup power arrangement: the BPS Unit and Sub Battery. Mazda identifies the Sub Battery as backup power for several systems when supply from the main battery is lost.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • A warning light and DTC P143B:00 may be found when the BPS identifies voltage drop from the Sub Battery.
  • Other driver-observable symptoms are not yet established by verified evidence.

6. Possible causes

  • Verified evidence associates P143B:00 with voltage down from the BPS and directs replacement of the Sub Battery.
  • Underlying reasons for the Sub Battery voltage condition 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

  • Arrange diagnosis or repair by a Mazda dealer or qualified technician.
  • Do not perform high-voltage or battery repair work yourself.
  • The cited Mazda communications state that regular maintenance-interval inspection and additional charging of the Sub Battery are not necessary.

10. Step-by-step troubleshooting

  1. Confirm the stored code is P143B:00 using appropriate diagnostic equipment.
  2. Have a qualified technician follow Mazda Workshop Manual procedures.
  3. Do not substitute additional charging for the documented repair direction; Mazda states additional charging is not necessary.

11. When to contact service

Contact a Mazda dealer or qualified service provider if P143B:00 is present. The verified Mazda communication directs Sub Battery replacement according to the Workshop Manual.

12. What the service center may check

  • Confirm whether the warning light/DTC is P143B:00.
  • Evaluate the BPS-reported voltage condition using Mazda diagnostic procedures.
  • Follow the applicable Workshop Manual procedure for Sub Battery replacement.

13. Possible repair or resolution

  • Replace the Sub Battery following the Mazda Workshop Manual procedure when P143B:00 is found based on voltage down from the BPS.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Mazda service information SA-017-23 and revisions (SA-017-23a, SA-017-23c through SA-017-23g) document the PHEV Sub Battery/BPS information and P143B:00 repair direction.
  • Mazda service information SA-020-24 and revisions (SA-020-24a through SA-020-24c) repeat the documented P143B:00 repair direction.
  • Official NHTSA-hosted source: https://static.nhtsa.gov/odi/tsbs/2024/MC-11010995-0001.pdf

16. Recall information

  • No recall is established by the supplied verified evidence.

17. Official manufacturer information

Applicable verified vehicles: US-market Mazda CX-70 model years 2024–2025 and Mazda CX-90 model years 2024–2025. The supplied Mazda/NHTSA manufacturer communications identify the BPS under the passenger-side foot support and state that scheduled inspection and additional charging are not necessary.

19. Frequently asked questions

What does Mazda P143B:00 indicate?

The verified Mazda communications associate it with voltage down from the BPS and direct replacement of the Sub Battery according to the Workshop Manual.

Does the Sub Battery need routine inspection or extra charging?

Mazda’s cited service communications state that inspection at regularly scheduled maintenance intervals and additional charging are not necessary.

Is P143B:00 a main high-voltage battery code?

Not yet established by verified evidence. The supplied evidence identifies a Sub Battery and BPS backup-power arrangement, separate from Mazda’s reference to the main battery.

20. Sources & verification

Verified
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