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Tesla DI_a166

Vehicle automatically parked to prevent rollaway Fasten seatbelt and close door to stay in gear

Common search variants: DIa166 · DI-a166 · DI a166 · Search ignores case and common separators.

DriveYes. Tesla documentation states that the vehicle is OK to drive in the meantime.
ChargeNot yet established by verified evidence.
ServiceSchedule Tesla service if DI_a166 persists throughout subsequent drives. Tesla documentation states that persistent alerts may require front motor inspection and service.
Confidence95%

Quick answer

DI_a166 means the Tesla automatically shifted into Park because it determined that the driver was leaving or was no longer present. Fasten the seatbelt and close the door to stay in gear.

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 DI_a166 mean?

DI_a166 means the Tesla automatically shifted into Park because it determined that the driver was leaving or was no longer present. Fasten the seatbelt and close the door to stay in gear.

2. Technical explanation

Tesla documentation submitted to NHTSA describes this as expected vehicle behavior under various circumstances. The vehicle automatically parks to help prevent rollaway when it determines the driver is leaving or no longer present. If the alert is absent when the next drive begins, the documentation says it was likely a temporary condition and no action is required. The same documentation states that the alert may also indicate a condition requiring front motor inspection and service.

3. What system is affected?

Automatic Park / rollaway-prevention behavior. A front motor inspection may be required if the alert persists, according to the verified Tesla documentation.

4. How serious is this code?

The diagnostic record lists severity as unknown. Tesla documentation says the vehicle is OK to drive in the meantime, but recommends service if the alert persists throughout subsequent drives.

5. Symptoms you may notice

  • The vehicle automatically shifts into Park (P).
  • The display shows: “Vehicle automatically parked to prevent rollaway. Fasten seatbelt and close door to stay in gear.”

6. Possible causes

  • The vehicle determined that the driver was leaving or was no longer present; this is documented as expected behavior under various circumstances.
  • A temporary condition, if the alert is no longer present at the start of the next drive.
  • A condition requiring front motor inspection and service, if the alert persists. No more specific cause is established by verified evidence.

7. Can I still drive the vehicle?

Yes. Tesla documentation states that the vehicle is OK to drive in the meantime.

8. Can I charge the vehicle?

Not yet established by verified evidence.

9. What you can safely do

  • Fasten the seatbelt and close the door to remain in gear.
  • If the alert is no longer present when the next drive begins, Tesla documentation states that no action is required.
  • If the alert persists throughout subsequent drives, schedule service.

10. Step-by-step troubleshooting

  1. At the next drive, check whether DI_a166 is still present.
  2. If it is no longer present, the verified documentation describes it as likely temporary.
  3. If it continues across subsequent drives, arrange Tesla service for evaluation. Do not attempt high-voltage or motor repairs yourself.

11. When to contact service

Schedule Tesla service if DI_a166 persists throughout subsequent drives. Tesla documentation states that persistent alerts may require front motor inspection and service.

12. What the service center may check

  • Verify whether DI_a166 persists throughout subsequent drives.
  • Inspect and service the front motor if indicated by Tesla’s diagnostic evaluation. Specific test steps are not established by verified evidence.

13. Possible repair or resolution

  • No repair is required when the alert is no longer present at the next drive, according to Tesla documentation.
  • If persistent, Tesla documentation recommends service and notes that front motor inspection and service may be required. The specific repair is not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication 10250480, published December 1, 2023: https://static.nhtsa.gov/odi/tsbs/2023/MC-10250480-9999.pdf
  • NHTSA Manufacturer Communication 10253666, published March 27, 2024: https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Verified NHTSA-hosted Tesla manufacturer communications describe DI_a166 and its recommended action. The supplied applicability records cover US Tesla Model 3 (2013–2024), Model S (2012–2024), Model X (2016–2024), and Model Y (2020–2024), with overlapping year ranges in the source data.

19. Frequently asked questions

What does Tesla alert DI_a166 mean?

It means the vehicle automatically shifted into Park because it determined the driver was leaving or was no longer present.

Can I drive with DI_a166?

Yes. Tesla documentation states that the vehicle is OK to drive in the meantime.

What should I do when this alert appears?

Fasten the seatbelt and close the door to stay in gear. If the alert persists throughout subsequent drives, schedule service.

Does DI_a166 always require repair?

No. If the alert is no longer present when the next drive begins, Tesla documentation says it was likely caused by a temporary condition and no action is required.

Why should persistent DI_a166 be inspected?

The verified documentation states that the alert may indicate a condition requiring front motor inspection and service.

20. Sources & verification

Accepted ResearchVerified
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Tesla DI_a166: Vehicle automatically parked to prevent rollaway Fasten… | EV Diagnostics