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BMW 8049AA

Coolant level sensor, expansion tank: Coolant level low or short circuit to ground or line disconnection

DriveNot yet established by verified evidence. BMW communication B170124 lists a possible Check Control message, “Drive, you can continue driving” (ID49), but this does not establish universal driving guidance for every occurrence of 8049AA.
ChargeNot yet established by verified evidence.
ServiceService need is not established by the supplied diagnostic record. Because this code concerns the coolant level sensor and the verified evidence does not identify the specific fault condition on the vehicle, qualified BMW diagnosis is appropriate.
Confidence97%

Quick answer

BMW fault code 8049AA means: “Coolant level sensor, expansion tank: Coolant level low or short circuit to ground or line disconnection.”

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 8049AA mean?

BMW fault code 8049AA means: “Coolant level sensor, expansion tank: Coolant level low or short circuit to ground or line disconnection.”

2. Technical explanation

Verified BMW manufacturer communications identify 8049AA as a coolant-level-sensor fault at the expansion tank. The documented fault description allows for a low coolant level, a short circuit to ground, or a disconnected circuit/line. The supplied evidence does not establish which of these conditions is present on any individual vehicle.

3. What system is affected?

Coolant level sensor and expansion tank.

4. How serious is this code?

Unknown. The verified database does not assign a severity level.

5. Symptoms you may notice

  • Low heater output may be present.
  • A Check Control message stating “Drive, you can continue driving” (ID49) may be present.
  • These symptoms are listed as possible in BMW manufacturer communication B170124; they are not established as present for every vehicle with 8049AA.

6. Possible causes

  • Coolant level low.
  • A short circuit to ground affecting the coolant level sensor circuit.
  • A line disconnection affecting the coolant level sensor circuit.
  • The verified evidence does not establish any further cause or identify which listed condition applies to a particular vehicle.

7. Can I still drive the vehicle?

Not yet established by verified evidence. BMW communication B170124 lists a possible Check Control message, “Drive, you can continue driving” (ID49), but this does not establish universal driving guidance for every occurrence of 8049AA.

8. Can I charge the vehicle?

Not yet established by verified evidence.

9. What you can safely do

  • Record the exact Check Control messages and stored fault codes.
  • Arrange diagnosis by a qualified BMW service provider.
  • Do not attempt high-voltage-system repair procedures.

10. Step-by-step troubleshooting

  1. Have a qualified technician confirm the stored fault code and assess the coolant level sensor and expansion-tank circuit in accordance with BMW diagnostic procedures.
  2. The verified evidence does not provide further step-by-step diagnostic instructions.

11. When to contact service

Service need is not established by the supplied diagnostic record. Because this code concerns the coolant level sensor and the verified evidence does not identify the specific fault condition on the vehicle, qualified BMW diagnosis is appropriate.

12. What the service center may check

  • Confirm whether 8049AA is stored.
  • Assess whether low heater output or Check Control message ID49 is present.
  • Diagnose the coolant level sensor, expansion tank, and associated circuit using BMW procedures.
  • The supplied evidence does not establish additional required checks.

13. Possible repair or resolution

  • Not yet established by verified evidence. The supplied BMW communication excerpt identifies the code and possible symptoms but does not provide a verified repair resolution.

14. Affected vehicles

15. Related TSBs / service bulletins

  • BMW manufacturer communication B170124 is documented through NHTSA as communications 10253344 (published 2024-04-26), 11014035 (2025-02-03), 11014422 (2025-02-11), 11016419 (2025-03-31), and 11029046 (2026-02-25). It lists 8049AA among possible fault codes in BEV vehicles with low heater output and/or possible Check Control message ID49.
  • The supplied evidence does not establish the full vehicle-specific applicability, repair procedure, or whether this communication applies to every instance of 8049AA.

16. Recall information

  • No recall information was supplied or established by verified evidence.

17. Official manufacturer information

Official evidence: BMW manufacturer communication B170124, published through NHTSA. NHTSA references supplied: 10253344, 11014035, 11014422, 11016419, and 11029046.

19. Frequently asked questions

What does BMW code 8049AA mean?

It means the expansion-tank coolant level sensor reports coolant level low, a short circuit to ground, or a line disconnection.

Can code 8049AA cause low heater output?

BMW communication B170124 lists low heater output as a possible condition in vehicles where 8049AA may be stored. It does not establish that 8049AA always causes low heater output.

Is it safe to drive with 8049AA?

Not yet established by verified evidence. The BMW communication lists a possible “Drive, you can continue driving” Check Control message (ID49), but no universal driving determination is supplied.

20. Sources & verification

Accepted ResearchVerified
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