Reflashing tips and tricks: Part I

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Reflashing tips and tricks: Part I

Portillo is the head technician of Car Clinic, a state-of-the-art automotive repair facility in Mahopac, N.Y. He is a protégé of Jerry Truglia and has been trained by Automotive Technician Training Service and is TST certified. His real-world, in-depth diagnostic articles will appear in Auto Service Professional on a regular basis.

Reprogramming is easy if you reflash the same vehicle all day, but it can get difficult if we work on several different makes and models. Here, we are going to cover how to reflash a selection of examples, using specific tools:

- Hyundai/Kia with a J2534 device

- Honda with the MVCI

- Toyota with the Techstream/J2534 device

- GM with a MDI/Drew Tech Mongoose Cable/J2534 device

- European vehicles using an Autologic

Reflashing a Hyundai

Reflashing a Hyundai is not only easy with a J2534 device, it is totally free. Here is how we do it:

1. (see Hyundai Figure 1): Go to and log in with your username and password.

2. (see Hyundai Figure 2): Click on “Diagnostic Tools” in the middle and click on “J2534 link.”

3. (see Hyundai Figure 3): Follow the instructions that appear on the screen. They are all standard stuff, such as put the vehicle KOEO and make sure a battery maintainer is on the car. Instructions on how to download the J2534 update program is on the same page.

4. (see Hyundai Figure 4): J2534HMA will be visible on the desktop. Simply double click on it.

5. (see Hyundai Figure 5): Simply click “OK.” The program will automatically look for flash updates.

6. (see Hyundai Figure 6): The program simply displays both the old and new Calibration IDs. Simply click OK to start the reflashing.

7. (see Hyundai Figures 7 and 8): The screen will say “reprogramming” during the event, but will not have any sort of status bar, so you will have to see the screen in Figure 8 to know that it is done. Then, simply click OK and you are done.


Reflashing Hondas

The "how to" reflash" a Honda is very easy to forget because Hondas very rarely need module updates. Honda has two programs to reflash modules. One is the free J2534 suite and the other is the OE software (which can be purchased for as little as $10 a day!).

Using the MVCI and a Honda subscription we can reflash any module by simply connecting to “CM Update,” which should download as a red shortcut on your desktop when you connect to the car and update your MVCI. On some versions of HDS, it will be a red button on the bottom of the screen.

Now, even more complicated that reflashing a module (which you will practically never do on a Honda) is coding a key. Here is how you do it:

1. (see Honda Figures 1 and 2): Start out by going to and click on the American flag. In Figure 2, you can see where a HDS subscription and a key code can be purchased. We are going to presume you have a HDS subscription and a “locksmith license” from and you’re going to get a key code. Click “click here to subscribe.”


2. (see Honda Figures 3 and 4): Click on “click here” at the bottom of Figure 3, choose the Honda service express subscription, and then click “checkout” in Figure 4.

3. (see Honda Figure 5): Scroll to the bottom and click “I agree.”

4. (see Honda Figure 6): After putting in all of your payment information click “Activate Subscription” on your online receipt.

5. (see Honda Figure 7): Put in your Honda username and password.

6. (see Honda Figure 8): Click “Keys and Codes” on the top right of the screen and for now, start up your HDS (Figure 9).

7. (see Honda Figure 10): Click “Immobi” to enter the immobilizer menu, in order to program keys.

8. (see Honda Figure 11): In this case, we are adding the keys because the PCM was replaced. Click “Replace ECM/PCM.” This begins a key registration process, in which after you are done you can update the PCM if necessary. Now, click the check mark on the bottom right of the screen.

9. (see Honda Figure 12): This screen simply gives you instructions in the event you have to reflash the PCM. Now, click the Check on the bottom right.]

10. (see Honda Figures 13 and 14): HDS (Figure 13) alerts us that we are going to obtain a “code” from Honda in order to continue the process. In Figure 8, we enter in our locksmith ID and password from and the VIN of the car. Then, the Honda website gives us the all important “PCM code,” here it is 5559.

11. (see Honda Figures 15 and 16): Simply enter in the PCM code into the vehicle and follow on screen instructions. When the process is complete, you can turn the key off and click the “exit” button.”

See Reflashing tips and tricks: Part II for Toyotas and GMs, and Part III for BMWs and Mercedes.

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Reflashing tips and tricks: Part III

Reflashing tips and tricks: Part II

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