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How To Check Transmission Control System MIL Request?

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The transmission control system is generally regarded as the essential part of the vehicle, and when it faces malfunctioning, the code P0700 is observed or seen. Whenever the code arises, it results in the illumination of a malfunction indicator lamp (MIL) in the vehicle. Have you ever seen poor mileage or having a transmission shifting problem? All these issues arise because of the faulty transmission control system in the car. Here, in this article, we are going to discuss the transmission control system MIL request. In its discussion, we will cover the cause and symptoms, the fixation techniques and cost, and the few most frequently asked questions further in the article.

Thus, after knowing the basics about the system, functioning, and working, let’s begin with the topic. And here, we will try our best to deliver the most acceptable and easiest ways to deal with the situation smoothly.

What Does Transmission Control System (MIL) Mean?

It is referred to as the P0700 trouble code, which triggers when a malfunction is detected in transmission controls. Modern cars have TCM or transmission control module, which provides the specific control module for the automatic transition system.

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The TCM is usually meant to monitor the transmission system’s sensor and send the data to the engine control module (ECM). If any data is detected in the design, then the P0700 code is activated or released.

The code is only responsible for detecting the problem in the system, whereas the cause needs to find by yourself. Whenever the transmission control system goes bad or malfunctions, it shows specific symptoms. The signs include slow acceleration, gear slippage, inability to shift, and poor fuel economy.

What Are Causes And Symptoms Of Transmission Control System MIL Request?

There are specific possible causes responsible for the generation of the trouble code in the vehicle. The most common reasons are – faulty reverse inhibit solenoid, open or shorted reverse inhibit control solenoid, bad reverse inhibit sensor and detective or a programming error in PCM. They are now moving on with the symptoms of the transmission control system MIL. These symptoms include, shifter goes to reverse while the vehicle is running forwards, the shifter cannot switch to reverse, and blown a fuse in transmission control-related circuits.

How To Check Transmission Control System MIL Request?

We would first suggest that before diagnosis, make sure the vehicle has a clean fluid and the transfer case filled to the appropriate mark. After completing the filling, you can start the diagnose of the MIL request.

Step 1:

First of all, retrieve all the data by connecting the diagnostic scanner and write the information regarding it before clearing the codes. Then we will recommend taking the car for a test drive until the PCM (powertrain control module) either enters readiness mode or reset.

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Whenever your PCM sets to readiness mode, then indeed, code is intermittent. It is pretty hard to diagnose in such an initial stage as the condition that caused the code may need to worsen more.

Step 2:

As soon as you are complete the previous step, i.e., code set, you may move to the next step. Try to correlate with the information source provided by your vehicle with the diagnostic flow chart available with the car.

Locate various things like connector pin-out chart, connector face views, and certain other specifications for the component testing procedure.

Step 3:

Now, in this step, test the voltage and ground circuits by using the DVOM. Soon after detecting both the voltage and ground, check the controller output also. Later, check the sensor-related and component to the specific symptoms of the vehicle.

If you find any of the components or systems that fail to comply with the recommended specifications, then it’s probably a defective one.

Step 4:

After conducting and testing all the related components, if you find the TCCS components are in good condition, then move to the test for the system circuit. The method usually opts for the test is the voltage drop testing method. Also, make sure to disconnect all controllers before testing for both your safety and get an accurate outcome.

How Do You Fix Transmission Control System malfunctioning?

There are multiple ways to fix the transmission related issues in the vehicle. Some of the most common points regarding the fixation are listed below:

1. Replace all the faulty, worn-out, and damage wires found during the diagnosis of the issue. Also, ensure that is all the connections are secure and safe.

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2. Locate the sources of transmission fluid leaks and replace all the faulty components.

3. Next, drain your transmission fluid, then remove and replace the filter. Soon after that, examine both the fluid and filter for debris. However, if you found any, then flush your system and put in fresh transmission fluid.

4. Also, replace the transmission shift solenoid if it’s damage.

5. Clear all the codes present and take a test drive after replicating the conditions of the initial failure.

How Much Does It Cost In Fixing The Transmission Control System?

The fixation cost generally depends on the root of the problem responsible for triggering the P0700 code in your vehicle. For instance, faulty or damaged transmission control system repair costs may range from $840 to $900. Labour cost lies between $100 to $126, whereas the parts are priced at $677.

The above-described range does not include taxes and fees. However, these prices may vary depending upon the place and the make and model of the vehicle.


We hope the information mentioned earlier guide and help you in dealing with your situation. Thus, the transmission control system is an essential part and responsible for controlling modern automotive transmissions based on input from various sensors and data provided by the engine control module. However, it is an easy process that must be performed step by step to attain the desired results.

Also, we expect that now you know about the transmission control system MIL request. However, if your doubts or queries regarding the topic persist, we request you to please comment below. And we will try to answer all your questions as soon as possible.