Autel Scanner Active Test: How to Check Electronic EGR Valve

The EGR valve plays a vital role in your car. It helps reduce the levels of harmful pollutants emitted by the internal combustion engine, particularly nitrogen oxides (NOx). However, a damaged EGR valve can severely impact the engine and emissions system.

Therefore, when an engine malfunctions, people often consider whether the EGR valve is faulty. At this time, the Autel scanner's bi-directional control function (active test) is often needed to diagnose and troubleshoot the fault to check whether the EGR valve is the problem.

Let's take a look at how to use the Autel scanner to detect the electronic EGR valve.

What is the EGR Valve?

The EGR valve (exhaust gas recirculation valve) is a core component in the engine's exhaust gas recirculation system, primarily used to control the amount of exhaust gas recirculation to optimize the combustion process and reduce emissions.

It reintroduces some exhaust gas into the intake manifold, lowering combustion chamber temperatures and thus reducing nitrogen oxide (NOx) emissions while improving fuel economy. The EGR valve is typically installed on the right side of the intake manifold and connected to the exhaust manifold via a metal tube.

EGR valves are divided into mechanical and electronic types. Today we will mainly introduce how to detect electronic EGR valves.

The EGR valve is an important component of the engine.

What is the Active Test(Bi-directional Control)?

Active Test means that the OBD2 scanner can send commands to the vehicle, and the scanner outputs signals to the vehicle control unit to control the actuator for testing. This includes a series of self-checks and test operations.

Through active testing, users can activate and control various components and systems on the vehicle, such as the engine, transmission, braking system, air conditioning system, etc. This enables users to proactively detect and verify whether various functions of the vehicle are working properly during the diagnostic process, helping to quickly locate faults.

Active testing is also known as bi-directional control of the scanner.

When do You Need to Test the Electronic EGR Valve?

Working Principle of EGR Valve

• At low engine loads or idling, the EGR valve is largely closed to maintain stable combustion.
• Under moderate loads and cruising conditions, the ECU (Engine Control Unit) controls the EGR valve to open, introducing a proportionate amount of exhaust gas.
• Under full-load acceleration, the EGR valve closes again to ensure the engine receives sufficient oxygen, enhancing power output.

Symptoms of EGR Valve Failure

When your car shows the following symptoms, it is often necessary to test whether the electronic EGR is faulty:

1. Check Engine Light Illuminates

   When the ECU detects problems such as abnormal EGR system flow or position feedback signal errors, the check light is activated and a DTC (DTC) is stored (common examples include P0401 and P0402).

2. Abnormal Engine Performance

   Idle Jitter or Stalling: When the EGR valve is stuck open, excessive exhaust gas enters the combustion chamber, resulting in a lean mixture.

   Weak Acceleration and Reduced Power: The EGR valve is stuck closed or half-open, causing abnormal exhaust gas circulation.

   

   If there is weak acceleration and power reduction, the EGR valve needs to be tested.

3. Excessive Emissions

   Excessively high nitrogen oxide (NOx) levels in exhaust gas testing may indicate that the EGR system is not functioning properly and requires testing to confirm.

4. Abnormal Noise or Severe Carbon Deposits

   Long-term carbon deposits may cause the EGR valve to stick. Testing can determine whether the valve is opening and closing properly.

5. After regular maintenance or replacement of related components

   After cleaning the throttle body or intake manifold, or replacing the EGR valve itself, it is recommended to use Active Test or a diagnostic tool to check whether its function has returned to normal.

If the vehicle experiences reduced power, unstable idle speed, abnormal emissions, or ECU errors, it is necessary to test the EGR valve using a diagnostic tool (such as the Autel Scanner).

Step-by-Step Active Test of EGR Valves with Autel

If your car exhibits the symptoms described above, you'll need to use an active auto diagnostic tool to test for a faulty EGR valve. Below is a guide to the entire EGR valve testing process using an Autel scanner. We hope this helps.

Step 1: Connect the Autel Scanner Correctly

Connect the vehicle to the Autel scanner via the car's OBD port. This can be done via a wired connection or via VCI if the vehicle is supported and equipped with a VCI device.

Step 2: Select the Diagnostics Menu

The main interface menu of the Autel scanner has many functions, including diagnostic functions, service functions, data management, etc. If you want to perform active test functions, you need to select the diagnostic menu to enter.

Access the EGR valve test from the diagnostic menu.

Step 3: Select and Confirm Vehicle Information

After selecting the diagnostic function, you need to select your vehicle information, including the brand, year of manufacture, VIN number, and possibly the engine model. However, if your Autel scanner supports automatic scanning and automatic VIN, the process will be very simple, such as using the Autel MP808Z-TS to test the EGR valve.

Step 4: Select the Appropriate Path for EGR Valve Testing

The specific selection path is as follows: diagnosis > control unit > Engine > Active test > EGR test.

The specific path selection may vary slightly due to the different car models and Autel scanner models. Please refer to the specific function path in the user manual.

Step 5: Tested according to the instructions of Autel scanner

After entering the EGR test, the Autel scanner will instruct you to activate the EGR valve and engine. Activate the EGR valve and monitor its response time. If the response time is within 3 seconds for opening and within 2 seconds for closing, this is normal.

During the test, all electrical devices must be turned off as instructed and the steering wheel must be in the center position.

Guide to testing EGR valve using Autel scanner

Step 6: Determine Whether the EGR Valve Is Faulty

The active test function allows you to troubleshoot or identify faults in just minutes, greatly facilitating vehicle maintenance. EGR valve malfunctions can be caused by carbon deposits or an electronic fault, resulting in extended opening and closing times. Simply repair the EGR valve based on the cause to resolve the issue.

Reference Video

The following video uses the 2003-2007 Honda Accord to test the electronic EGR valve (exhaust gas recirculation valve) as an example. The operation steps are for reference only. The specific operation steps may vary depending on the vehicle and scan tool:

Summary

Active Test is a very useful feature of the Autel scanner. It helps you quickly troubleshoot and identify the cause of a problem, playing an important role in vehicle maintenance.

The EGR valve plays a vital role in the vehicle engine system. If a vehicle malfunctions, you can use the Autel scanner's Active Test feature to check the EGR valve and help troubleshoot and identify the problem.