What is OBD-II Code P2AF9 – Starter Relay D Control Circuit High

What is OBD-II Code P2AF9 – Starter Relay D Control Circuit High

As an experienced mechanic, I know that when a vehicle’s check engine light comes on, it can be worrisome and confusing for the average person without technical knowledge. One specific code that may appear in this situation is OBD-II Code P2AF9, otherwise known as “Starter Relay D Control Circuit High.” In this article, I will explain what this code means, its potential causes, and how to repair the issue.

Understanding OBD-II Codes

Before delving into Code P2AF9 specifically, it’s important to understand what OBD-II codes are and how they work. OBD, or On-Board Diagnostics, is a system built into vehicles that monitor various components and systems to ensure they are functioning correctly. If a problem is detected, the OBD system will often trigger a warning light on the dashboard or store a specific code in the vehicle’s computer.

There are two types of OBD-II codes: generic and manufacturer-specific. Generic codes are the same for all OBD-II vehicles and generally start with the letter “P.” Manufacturer-specific codes, on the other hand, are unique to each individual carmaker and start with a letter designated by the manufacturer, such as “U” for Ford or “B” for General Motors.

Code P2AF9 Explanation

Now that you have a better understanding of OBD-II codes, let’s talk about Code P2AF9 and what it means. This code is specific to Ford vehicles and indicates an issue with the Starter Relay D Control Circuit. The letter “D” refers to a specific circuit in the car’s system, so it’s important to know which circuit this letter corresponds to before diagnosing the problem.

When this code appears, it means that the Starter Relay D Control Circuit has reported a high voltage reading, indicating that there may be an issue with the starter relay or the wiring associated with it. This could cause problems with starting the vehicle, as the relay is responsible for connecting the battery to the starter motor.

Common Causes of Code P2AF9

Once you know what Code P2AF9 means, it’s important to assess the potential causes of the issue to diagnose and repair the problem. Some common causes of this code include:

1. Faulty starter relay: A defective relay could cause an abnormal voltage reading, leading to the code being triggered.

2. Corroded wiring: Corrosion can cause resistance in the wiring, leading to a high voltage reading.

3. Damaged starter: If the starter is damaged, it could cause abnormalities in the wiring and cause the code to be triggered.

4. Loose connections: Loose or damaged wiring connections can cause an increase in voltage and lead to this code being triggered.

Repairing Code P2AF9

Once the potential cause of this code has been diagnosed, it’s time to address how to repair the issue. Depending on the specific cause, options for repair may include:

1. Replace the starter relay: If a faulty starter relay is determined to be the cause, it will need to be replaced with a new one.

2. Repair or replace corroded wiring: If corrosion is found to be the issue, the affected wiring will need to be cleaned or replaced to eliminate resistance.

3. Replace the starter: If the starter is damaged, it will need to be replaced entirely to resolve the issue.

4. Tighten or replace damaged wiring connections: Any loose or damaged wiring connections should be tightened or replaced to eliminate voltage abnormalities.

Frequently Asked Questions

1. What does OBD-II Code P2AF9 indicate?

A. Code P2AF9 indicates an issue with the Starter Relay D Control Circuit in Ford vehicles.

2. What are the potential causes of Code P2AF9?

A. Potential causes of this code include a faulty starter relay, corroded wiring, a damaged starter, or loose connections.

3. How do I diagnose Code P2AF9?

A. Diagnosing this code requires assessing the specific circuit associated with the letter “D” and assessing the potential causes mentioned above.

4. How do I repair Code P2AF9?

A. To repair the issue, you may need to replace the starter relay, repair or replace corroded wiring, replace the starter, or tighten or replace damaged wiring connections.

5. Can I still drive my car with Code P2AF9?

A. While it is possible to continue driving your car with Code P2AF9, it is not recommended, as it could lead to further damage.


Understanding OBD-II codes and what they mean is crucial for ensuring the longevity and safety of your vehicle. Code P2AF9, specifically, indicates an issue with the Starter Relay D Control Circuit in Ford vehicles, which could cause problems with starting the car. By assessing the potential causes and repairing the issue accordingly, you can ensure your vehicle is running correctly and avoid more significant problems down the line.

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