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Porsche Reduced speed

Reduced speed

DriveUnknown as a general determination. In the documented calibration context, Porsche states that a road permitting acceleration to at least 60 km/h (38 mph) can be used, subject to suitable road and traffic conditions and applicable traffic regulations.
ChargeUnknown; not yet established by verified evidence.
ServiceContact an authorized Porsche service provider, particularly if “Reduced speed” appears unexpectedly, persists, or is accompanied by other warnings.
Confidence90%

Quick answer

For certain 2020–2021 US Porsche Taycan vehicles, the instrument-cluster message “Reduced speed” is documented after high-voltage power-electronics resetting. Verified service information states that maximum vehicle speed is limited to 70 km/h (43 mph) during this condition.

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 Reduced speed mean?

For certain 2020–2021 US Porsche Taycan vehicles, the instrument-cluster message “Reduced speed” is documented after high-voltage power-electronics resetting. Verified service information states that maximum vehicle speed is limited to 70 km/h (43 mph) during this condition.

2. Technical explanation

Porsche service communication No. 120-21 states that resetting the high-voltage power electronics limits maximum vehicle speed to 70 km/h (43 mph) and displays the warning message “Reduced speed” in the instrument cluster. The cited communications describe a calibration drive following that reset. The supplied evidence does not establish that every occurrence of this message has the same cause.

3. What system is affected?

High-voltage power electronics.

4. How serious is this code?

Unknown. The verified evidence confirms a speed limitation but does not assign a severity classification.

5. Symptoms you may notice

  • “Reduced speed” displayed in the instrument cluster.
  • Maximum vehicle speed limited to 70 km/h (43 mph) after high-voltage power-electronics resetting.

6. Possible causes

  • Resetting the high-voltage power electronics, in the specific service/calibration context described by Porsche communication No. 120-21.
  • Other causes are not yet established by verified evidence.

7. Can I still drive the vehicle?

Unknown as a general determination. In the documented calibration context, Porsche states that a road permitting acceleration to at least 60 km/h (38 mph) can be used, subject to suitable road and traffic conditions and applicable traffic regulations.

8. Can I charge the vehicle?

Unknown; not yet established by verified evidence.

9. What you can safely do

  • Observe the displayed speed limitation.
  • Do not exceed applicable speed limits or drive contrary to road and traffic conditions.
  • Arrange Porsche service assessment if the message appears outside a known service/calibration procedure or remains present.

10. Step-by-step troubleshooting

  1. Verify whether the vehicle recently underwent a high-voltage power-electronics reset or related Porsche calibration procedure.
  2. Have a qualified Porsche service provider evaluate the vehicle. Further owner troubleshooting is not established by verified evidence.

11. When to contact service

Contact an authorized Porsche service provider, particularly if “Reduced speed” appears unexpectedly, persists, or is accompanied by other warnings.

12. What the service center may check

  • Confirm whether high-voltage power electronics were reset.
  • Use the Porsche service procedure and calibration-drive process referenced in communication No. 120-21.
  • Follow Porsche safety instructions and applicable road traffic regulations during any required calibration drive.

13. Possible repair or resolution

  • In the documented service scenario, Porsche calls for a calibration drive after resetting the high-voltage power electronics.
  • A general repair resolution for all “Reduced speed” alerts is not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Porsche No. 120-21, reported to NHTSA as Manufacturer Communication 10200890 (published August 24, 2021).
  • Porsche No. 120-21, reported to NHTSA as Manufacturer Communication 10205973 (published December 17, 2021).
  • Porsche No. 120-21, reported to NHTSA as Manufacturer Communication 11023001 (published August 30, 2025).

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Porsche manufacturer communications: https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2020-2024.zip#nhtsa_id=10200890 ; https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2020-2024.zip#nhtsa_id=10205973 ; https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2025-2026.zip#nhtsa_id=11023001

19. Frequently asked questions

What does “Reduced speed” mean on a Porsche Taycan?

For the documented No. 120-21 service scenario, it means the high-voltage power electronics have been reset and maximum vehicle speed is limited to 70 km/h (43 mph).

Does the warning always mean the same thing?

No general conclusion is established by the supplied evidence. The evidence documents this message in a specific high-voltage power-electronics reset and calibration context.

Which vehicles are covered by the supplied applicability data?

The supplied data identifies US-market 2020–2021 Porsche Taycan vehicles.

20. Sources & verification

Verified
Porsche Reduced speed: Reduced speed | EV Diagnostics