AutoCodes – Volkswagen – P0599 Volkswagen

P0599 Volkswagen Code - Thermostat Heater Control Circuit High

Quick Answer

The Engine Control Module (ECM) controls the Pulse Width Modulated (PWM) thermostat. Common causes include Failed Engine Cooling Thermostat, Engine Cooling Thermostat harness is open or shorted, Engine Cooling Thermostat circuit poor electrical connection. 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 Volkswagen indicates Thermostat Heater Control Circuit High.
Common causes: Common causes include Failed Engine Cooling Thermostat, Engine Cooling Thermostat harness is open or shorted, Engine Cooling Thermostat circuit poor electrical connection.
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.

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Code Popularity 11,319

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 27, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0599 Volkswagen Description

The Engine Control Module (ECM) controls the Pulse Width Modulated (PWM) thermostat. The engine coolant thermostat heater controls coolant flow and regulates the engine operating temperature. The ECM supplies 12 V to the thermostat. The ECM controls the engine coolant thermostat heater by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

OBDII Code P0599 Volkswagen - Thermostat Heater Control Circuit High - AutoCodes.com — P0599 Volkswagen Code - Thermostat Heater Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P0599 Volkswagen?

Failed Engine Cooling Thermostat
Engine Cooling Thermostat harness is open or shorted
Engine Cooling Thermostat circuit poor electrical connection

How to Fix the DTC P0599 Volkswagen?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0599 Volkswagen code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 Volkswagen Code

1. What are the common symptoms of OBDII code P0599 in a Volkswagen related to the thermostat heater control circuit high?

The common symptoms include the engine overheating, the temperature gauge showing high readings, and the Check Engine Light illuminating on the dashboard.

2. What can cause the OBDII code P0599 (Thermostat Heater Control Circuit High) to trigger in a Volkswagen?

The code P0599 typically triggers in a Volkswagen due to a malfunction in the thermostat heater control circuit, which can be caused by issues such as a faulty thermostat, a damaged wiring harness, or a defective thermostat heater control module.

3. How serious is the OBDII code P0599 in a Volkswagen?

The OBDII code P0599 related to the thermostat heater control circuit high is considered moderately serious. While it may not cause immediate breakdown or severe damage, it can lead to engine overheating and potential long-term issues if not addressed promptly.

4. Can I continue driving my Volkswagen with the OBDII code P0599 present?

It is not recommended to continue driving your Volkswagen with the OBDII code P0599 present, as it can lead to engine overheating and potential damage. It is best to address the issue as soon as possible.

5. How can I diagnose the OBDII code P0599 in my Volkswagen?

Diagnosing the OBDII code P0599 involves using a diagnostic scanner to retrieve the trouble codes, inspecting the thermostat heater control circuit for any visible damage, and testing the thermostat and related components for proper functionality.

6. What are some repair tips for fixing the OBDII code P0599 in a Volkswagen?

Repair tips for fixing the OBDII code P0599 may include replacing the thermostat, repairing or replacing damaged wiring, checking and replacing the thermostat heater control module if necessary, and clearing the trouble codes with a diagnostic scanner.

7. Is it possible to reset the OBDII code P0599 in a Volkswagen without fixing the underlying issue?

While you can temporarily clear the code using a diagnostic scanner, it is not recommended to reset the code without addressing the underlying issue causing the thermostat heater control circuit high malfunction. Ignoring the problem can lead to further complications.

8. How much does it typically cost to repair the OBDII code P0599 in a Volkswagen?

The cost of repairing the OBDII code P0599 in a Volkswagen can vary depending on the underlying issue, the extent of the damage, and the labor rates of the repair shop. It is advisable to consult a professional mechanic for an accurate estimate.

9. Can a DIY enthusiast fix the OBDII code P0599 in a Volkswagen?

While some experienced DIY enthusiasts may be able to diagnose and repair the OBDII code P0599 in a Volkswagen, it is generally recommended to seek assistance from a qualified mechanic due to the complexity of the thermostat heater control circuit and potential electrical hazards.

10. How can I prevent the OBDII code P0599 from recurring in my Volkswagen?

To prevent the OBDII code P0599 from recurring in your Volkswagen, it is essential to perform regular maintenance on the cooling system, address any overheating issues promptly, and ensure all thermostat-related components are in good working condition.