What is OBD-II Code P028D – Charge Air Cooler Cooling Fan Control Circuit Low

The Check Engine Light (CEL) is one of the most dreaded signals on a car dashboard. It can indicate several issues, ranging from minor inconveniences to serious problems. When the CEL light comes on, it means that your vehicle’s onboard diagnostic (OBD) system has detected a problem. The OBD-II Code P028D is one of the most common codes that mechanics come across. This code relates to a problem with Charge Air Cooler (CAC) Cooling Fan Control Circuit Low. In this article, we will discuss what P028D means, how to diagnose the problem causing it, and how to fix it.

What is OBD-II Code P028D?

The OBD-II Code P028D indicates a problem with Charge Air Cooler (CAC) Cooling Fan Control Circuit Low. This code means that the CAC system’s cooling fan is not working correctly or not working at all. The CAC system is responsible for cooling the compressed air after it leaves the turbocharger or supercharger. The cooling fan ensures that the temperature of the compressed air is maintained within the required range. When the CAC system’s cooling fan is not functioning properly, the engine’s performance may be significantly affected, leading to a decrease in fuel efficiency and increased emissions.

What Causes OBD-II Code P028D?

Several factors can cause the OBD-II Code P028D. The common causes include:

1. Faulty CAC Cooling Fan – The cooling fan’s failure will prevent the compressed air from being cooled properly, leading to the P028D code.

2. Poor Electrical Connection – Corroded, damaged, or loose electrical connections can lead to incomplete or no power reaching the CAC cooling fan, leading to the P028D code.

3. Blown fuse – A blown fuse will cause the CAC cooling fan to stop functioning, leading to the P028D code.

4. Malfunctioning CAC Sensor – Malfunctioning CAC Sensors can cause the CAC cooling fan to stop working, causing the P028D code.

How to Diagnose OBD-II Code P028D

To diagnose OBD-II Code P028D, the following steps are required:

1. Use an OBD-II scanner to read and locate the P028D code. The scanner can determine if there are any other codes present that could affect the cooling fan’s operation.

2. After locating the problem, inspect the wiring and connectors leading to the CAC sensor, cooling fan, and the CAC system’s control module. Ensure that the connections are clean, free from corrosion, and properly seated.

3. Inspect the fan for physical damage, corrosion, and any other signs of wear and tear. Replace the fan if necessary.

4. Check the fuse that powers the CAC cooling fan. If it’s blown, replace it.

5. Test the cooling fan motor using a multimeter to check for continuity. If the fan motor fails to produce continuity, replace the fan.

How to Fix OBD-II Code P028D

To fix OBD-II Code P028D, you need to take the following steps:

1. Inspect and fix any faulty connections or wires leading to the CAC system’s control module, cooling fan, and CAC sensor. Ensure they are free from damage and clean.

2. Replace any damaged, corroded, or worn-out parts such as the cooling fan or CAC sensor.

3. If it is necessary, take your car to your mechanic for further inspection.

Frequently Asked Questions (FAQs)

1. How much does it cost to fix the P028D Code?

The cost of fixing P028D code can vary depending on what caused it. The cost can range from as low as $50 to over $500, depending on the underlying issue.

2. Can I drive my car with the P028D Code?

While it is safe to drive your car with the P028D code, it is not advisable. The code indicates a cooling system problem that can lead to reduced fuel efficiency and emissions. It is always best to fix the problem as soon as possible to prevent further engine damage.

3. Can I clear the P028D code by disconnecting the battery?

Disconnecting the battery will clear the P028D code, but it is not recommended. The CEL light may turn off temporarily, but the code will reappear once the car detects the problem again. It’s always recommended to follow proper diagnostic procedures and fix the underlying issue.

4. What other problems may be associated with the P028D code?

The P028D code may cause other problems such as reduced engine power, decreased fuel efficiency, and increased emissions.

5. Can P028D code affect my car’s warranty?

If your car is within the warranty period, P028D code can be covered under the manufacturer’s warranty. However, if you have modified your car, the warranty may not cover the P028D code.


OBD-II Code P028D indicates a problem with the Charge Air Cooler Cooling Fan Control Circuit Low. Diagnosing and fixing the underlying issue is crucial because it can impact your car’s fuel efficiency, emissions, and overall performance. The most common causes of the P028D code are a faulty CAC cooling fan, poor electrical connections, blown fuses, and malfunctioning CAC sensors. To fix the problem, you should inspect the wiring and connectors, test the fan motor, and replace any damaged or worn-out parts. If you’re unsure, it’s always best to take your car to your mechanic to ensure a comprehensive diagnosis and fix.

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