Engine-CodesBMW – P0599 BMW

P0599 BMW Code - Thermostat Heater Control Circuit High

Quick Answer

The P0599 code for BMW indicates an issue with the thermostat heater control circuit being detected as too high. Common causes include Faulty thermostat heater, Wiring issues in the thermostat heater circuit, Corrosion or damage to electrical connectors. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0599 BMW indicates Thermostat Heater Control Circuit High.
Common causes
Common causes include Faulty thermostat heater, Wiring issues in the thermostat heater circuit, Corrosion or damage to electrical connectors.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P0599 BMW Description

The P0599 code for BMW indicates an issue with the thermostat heater control circuit being detected as too high. The thermostat heater is responsible for regulating the engine's operating temperature by controlling the flow of coolant through the engine. When the engine temperature is too low, the thermostat heater warms up the coolant to bring the engine to the optimal temperature for efficient operation.

OBDII Code P0599 BMW - Thermostat Heater Control Circuit High
P0599 BMW Code - Thermostat Heater Control Circuit High

Common Causes of P0599 BMW

  1. Faulty thermostat heater
  2. Wiring issues in the thermostat heater circuit
  3. Corrosion or damage to electrical connectors
  4. ECM software issues
  5. Coolant leaks affecting thermostat heater operation

Symptoms of P0599 BMW

  1. Engine overheating
  2. Slow engine warm-up
  3. Decreased fuel efficiency
  4. Illuminated Check Engine Light
  5. Poor heater performance in the cabin

How to Fix P0599 BMW

  1. Begin by diagnosing the root cause of the issue by checking the thermostat heater and its circuit for any faults.
  2. Inspect the wiring and connectors for any signs of damage or corrosion, and repair or replace as necessary.
  3. Test the thermostat heater to ensure it is functioning properly, and replace it if it is found to be faulty.
  4. Clear the diagnostic trouble codes from the ECM and test drive the vehicle to ensure the issue has been resolved.
  5. Monitor the engine temperature and heater performance to confirm that the thermostat heater control circuit is functioning correctly.

Cost to Fix P0599 BMW

The cost of repairing a P0599 code on a BMW can vary depending on the specific cause of the issue and the labor rates in your area. Generally, the cost of parts for a thermostat heater replacement can range from $150 to $400, while the labor cost can range from $100 to $300. Overall, you can expect to pay anywhere from $250 to $700 for this repair. It's recommended to consult with a trusted mechanic or BMW specialist for a more accurate estimate based on your vehicle's specific circumstances.

Tech Notes for P0599 BMW

If there are no coolant system leaks, replace the thermostat to fix the problem.

When is the Code Detected?

The P0598 is triggered when there is an open or short thermostat heather control circuit.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0599 BMW Code

1. What does the OBDII code P0599 mean on a BMW?

The P0599 code indicates a problem with the thermostat heater control circuit, specifically that the circuit is registering a high voltage condition.

2. What are the common symptoms of a P0599 code on a BMW?

Symptoms may include the check engine light turning on, engine overheating or running cooler than normal, reduced fuel efficiency, and poor heater performance.

3. What causes the P0599 code to appear in a BMW?

Common causes include a faulty thermostat, damaged thermostat heater control wiring, corroded electrical connectors, or a malfunctioning engine control module (ECM).

4. Can I continue driving my BMW with a P0599 code?

While it may be safe to drive for short distances, ignoring this code can lead to engine overheating or inefficient operation, potentially causing further damage.

5. How is the P0599 code diagnosed on a BMW?

A mechanic will typically use a scan tool to confirm the code, visually inspect wiring and connectors, and test the thermostat heater circuit and related components for proper function.

6. What repairs are needed to fix the P0599 code on a BMW?

Repairs may include replacing the thermostat, repairing or replacing damaged wiring or connectors, or in rare cases, reprogramming or replacing the engine control module.

7. Is the thermostat the only component that can cause the P0599 code?

No, other issues like short circuits, open circuits, or problems within the ECM can also trigger this code.

8. How much does it cost to repair a P0599 code on a BMW?

The cost can vary depending on the specific issue, but replacing the thermostat typically costs between $150 and $400, including parts and labor.

9. Can a P0599 code affect my BMW’s fuel efficiency?

Yes, a malfunctioning thermostat can cause the engine to run at incorrect temperatures, leading to reduced fuel efficiency.

10. How can I prevent the P0599 code from recurring on my BMW?

Regular maintenance, including inspecting wiring and connectors and ensuring the cooling system is in good condition, can help prevent this code from returning.

Discuss the causes and fixes for P0599 BMW OBDII Code

  • But what if I do have a leak how do I fix the problem

  • Fyi I fix the small thermosat and I am leaking from the expansion tank

  • You need to find out where the leak is coming from and replaced or repair the part. If for example the leak comes from a radiator hose, then replaced the hose and clear the code

  • How did you fix the thermostat?

    If the leak comes from the expansion tank, then you need to repair or replaced the tank.

  • had to fix this but in order for a shop to fix it they had to buy a part from bmw so it was like $399 or 400$