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Tesla CP_a079

Charge rate reduced - Charge port may be frozen Try using Defrost Car button in Mobile App

Common search variants: CPa079 · CP-a079 · CP a079 · Search ignores case and common separators.

DriveNot yet established by verified evidence.
ChargeCharging may continue at a reduced rate when this alert is present. Verified evidence specifically describes reduced AC charging when the latch is not engaged; overall charging suitability is not yet established by verified evidence.
ServiceService need is not yet established by verified evidence.
Confidence95%

Quick answer

Tesla alert CP_a079 means the charge rate is reduced because the charge-port latch cannot secure the charge cable while cold ambient temperature is detected; the latch may be frozen. Tesla directs the owner to try the Defrost Car button in the mobile app.

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 CP_a079 mean?

Tesla alert CP_a079 means the charge rate is reduced because the charge-port latch cannot secure the charge cable while cold ambient temperature is detected; the latch may be frozen. Tesla directs the owner to try the Defrost Car button in the mobile app.

2. Technical explanation

Verified Tesla owner-manual material submitted to NHTSA states that CP_a079 occurs when the charge-port latch is unable to secure the charge cable in the charge-port inlet and cold ambient temperature is detected. When the latch is not engaged, AC charging, such as with a Mobile Connector or Wall Connector, is reduced. The alert message identifies a possibly frozen charge port and recommends Defrost Car in the Tesla mobile app.

3. What system is affected?

Charge port latch / charge cable retention during AC charging.

4. How serious is this code?

Unknown. The verified database does establish reduced charging, but does not assign a severity classification.

5. Symptoms you may notice

  • CP_a079 alert is displayed.
  • Charge rate is reduced.
  • Cold ambient temperature is detected.
  • The charge-port latch is unable to secure the charge cable in the inlet.

6. Possible causes

  • The charge-port latch may be frozen in cold ambient conditions.
  • Verified evidence specifically establishes that the latch is unable to secure the cable while cold ambient temperature is detected.

7. Can I still drive the vehicle?

Not yet established by verified evidence.

8. Can I charge the vehicle?

Charging may continue at a reduced rate when this alert is present. Verified evidence specifically describes reduced AC charging when the latch is not engaged; overall charging suitability is not yet established by verified evidence.

9. What you can safely do

  • Use the Defrost Car button in the Tesla mobile app, as directed by the alert.
  • Refer to the applicable Tesla owner’s manual charging instructions for the vehicle.

10. Step-by-step troubleshooting

  1. Try Defrost Car in the Tesla mobile app.
  2. Confirm whether the charge cable can be secured by the charge-port latch after using Defrost Car. Further diagnostic steps are not yet established by verified evidence.

11. When to contact service

Service need is not yet established by verified evidence.

12. What the service center may check

  • Not yet established by verified evidence.

13. Possible repair or resolution

  • Not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA manufacturer communications containing Tesla owner-manual material document CP_a079, including NHTSA communication 10253666 (published March 27, 2024): https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf
  • The supplied evidence identifies these as official manufacturer communications/owner-manual documentation; it does not establish a repair TSB or prescribed repair for CP_a079.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Tesla documentation: https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf. Verified applicability is US Tesla Model 3 (2013–2024), Model S (2012–2024), Model X (2016–2024), and Model Y (2020–2024), with overlapping source records for some year ranges.

19. Frequently asked questions

What does Tesla CP_a079 mean?

It means the charge rate is reduced because the charge-port latch cannot secure the charging cable and cold ambient temperature is detected; the charge port may be frozen.

What should I try first?

Tesla directs the owner to try the Defrost Car button in the Tesla mobile app.

Why is charging reduced?

The verified documentation states that AC charging is reduced when the charge-port latch is not engaged.

Is it safe to drive?

Not yet established by verified evidence.

20. Sources & verification

Accepted ResearchVerified
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Tesla CP_a079: Charge rate reduced - Charge port may be frozen Try… | EV Diagnostics