P0599 code — how to fix error fast

Some OBD2 error codes are simply worse than others that may indicate “lighter” issues and the P0599 code is certainly one of them. This code often occurs along with some other symptoms including higher engine temperatures and overheating, so it takes knowing more about the P0599 code meaning and what it does in your car to figure things out.

Our team is therefore here to help you out as we navigate through the common issues and diagnostic methods of the code together. We’ll also discuss how you can fix and prevent the code from happening again, so stay tuned for detailed instructions.

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What does the P0599 code mean?

The P0599 code is related to the thermostat heater control circuit. It indicates that there is a malfunction in the thermostat heater control circuit. The thermostat is an important component of the engine’s cooling system, and its primary function is to regulate the engine’s operating temperature. The thermostat heater control circuit is responsible for maintaining the correct temperature of the engine.

If the P0599 code appears, it means that there is a problem with the thermostat heater control circuit, which can result in the engine running at a higher or lower temperature than it should. This can cause serious damage to the engine and other components of the vehicle if not addressed promptly.

What causes the P0599 code?

The code P0599 can be triggered by several things and most of these tend to be associated with the thermostat’s heater. However, it takes knowing exactly what’s the root cause of the issue to fix it so here’s a complete overview:

Faulty thermostat

If the thermostat is faulty and fails to open or close properly, it can cause the engine to run too hot or too cold. This can lead to a variety of issues, including reduced performance, increased emissions, and potential damage to engine components that all lead to the code P0599 being displayed.

Faulty thermostat heater

A faulty thermostat heater can also cause damage to other engine components, such as the ECT sensor. The ECT sensor measures the temperature of the engine coolant and sends this information to the ECM. If the thermostat heater is not functioning properly, it can cause inaccurate readings from the ECT sensor, which can lead to incorrect fuel injection and ignition timing and this leads to the code P0599.

Failed temperature sensor

The Engine Coolant Temperature (ECT) sensor is a vital component of the engine control system. It measures the temperature of the engine coolant and sends this information to the Engine Control Module (ECM). The ECM uses this data to adjust the fuel injection and ignition timing to optimize engine performance. If there is an issue with the ECT sensor, it can cause the P0599 code to be triggered.

Wiring issues

Wiring issues are one of the most common causes of problems with the thermostat heater control circuit. The wiring in the system may become damaged or corroded over time due to exposure to heat and moisture. This can cause electrical resistance in the circuit, which can prevent the thermostat heater from functioning properly.

Which car models does the P0599 code affect the most?

The P0599 code can affect various car models, but some models are more prone to the issue than others. These models have a common issue with the thermostat heater control circuit, which can cause the P0599 code to appear, so here’s our complete list:

• Chevy Cruze: This car has an issue with the ECT sensor that’s prone to failure and that’s why it’s prone to damage caused by the code P0599.
• Chevrolet Sonic: This model has problems with the wiring that affects the performance of the thermostat heater and leads to the code P0599 triggering.
• GMC Terrain: This model is prone to code P0599 due to the failing temperature sensor.

How to diagnose the P0599 code

Diagnosing the P0599 code requires specialized diagnostic tools and knowledge of the vehicle’s cooling system. Here are the steps to diagnose the P0599 code:

Use an OBD2 scanner

You can use an OBD-II (On-Board Diagnostics) scanner to read the fault codes stored in the car’s onboard computer system. The scanner can provide information about the specific code that has been triggered, as well as any other codes that may be present.

Check the resistance of the heater’s circuit

A multimeter can be used to test the resistance and continuity of the thermostat heater control circuit. This can help identify any issues with wiring or other components in the circuit.

Replace faulty components

If a faulty component is identified during the diagnostic process, such as a failed ECT sensor or thermostat, it may need to be replaced to resolve the issue.

How to fix the P0599 code

There are several main ways of fixing the code P0599 and they all have to do with repairing or replacing faulty components that affect the thermostat. Here’s what you can do to restore balance to your car’s cooling system and prevent similar issues from occurring in the future:

Replace or repair damaged wiring

If a wiring issue is identified as the cause of the problem, a mechanic may repair or replace any damaged wiring in the thermostat heater control circuit.

Replace faulty components

If a faulty component, such as a failed ECT sensor or thermostat, is identified as the cause of the problem, it may need to be replaced to resolve the issue.

Deal with corroded connections

Corroded connections in the thermostat heater control circuit can cause issues with electrical resistance and prevent proper operation of the system. A mechanic may clean any corroded connections or terminals to restore proper function to the circuit.

Checking for software updates

In rare cases, a software update from the manufacturer may be required to address issues with the thermostat heater control circuit.

How to prevent the P0599 code

Preventing the P0599 code requires proper maintenance of the vehicle’s cooling system. Here are some preventative measures you can take:

• Follow the manufacturer’s recommended maintenance schedule for the vehicle’s cooling system.
• Regularly inspect the thermostat and thermostat housing for signs of wear or damage.
• Inspect the wiring in the thermostat heater control circuit for damage or loose connections.
• Use high-quality replacement parts when replacing any components of the cooling system.

By following these preventative measures, you can help ensure that your vehicle’s cooling system is functioning properly and reduce the risk of the P0599 code appearing.

Our take

Overall, any code that can potentially be caused harmful problems for your engine should be handled immediately, and the same goes for the code P0599. That’s why we wanted to give you a complete list of affected models, causes of the problem, and ways of diagnosing and fixing it to help you out.

We are confident that this guide will serve you well on the road to erasing the code and restoring proper engine temperature.