Reprogramming your computer for the right reasons can be beneficial for the car's performance. However, reprogramming it for the wrong reasons is not going to result in desired outcomes. Since 1996, when the implementation of OBD (on-board diagnostics) II was integrated into automobiles, the electronic control module, the powertrain control module and the transmission control module became standard features on many cars. These computerized devices interlink as one or more units and communicate vehicle diagnostics. If trouble codes or vehicle performance becomes an issue, reprogramming or upgrading the software for the computer may help.

Right Simple Way

A pass-through tool accompanied with the upgraded vehicle software will be required to safely and effectively upgrade or reprogram the computer in your car. This procedure is only available for OBD II systems. Although a very simple task, be aware that it will cost you money for the service or equipment to do so. The pass-tool is plugged into the data link connector of the vehicle, usually located beneath the driver's side instrument panel. The USB port is then plugged into a laptop computer or a scan tool with the uploaded software for the vehicle preinstalled. For the laptop, you can access the manufacturers web page and located the correct software for the vehicle. Upload it into the laptop, and it will send the information to the computer of the car via the USB port connection. During this process, no interruptions can occur. Laptops using a dial-up modem are not recommended.

Wrong Simple Way

An effective and sometimes inexpensive simple way to reprogram the computer on a car is to manually reboot it. No new upgrades will be added to the computer, but simple communication errors may reset properly. This procedure is geared more towards older vehicles prior to the standardization of OBD II data link connectors. To do this, unhook the negative battery terminal on the vehicle. Since a slight charge from the battery to the computer still exists internally, turn the ignition key to on in order to discharge the remaining charge. This will shut the computer down, and it will have to reboot once the battery is reconnected. Be aware that this procedure, although it can be performed on OBD II systems, is not highly recommended. Computers in cars employ memory for all facets of the vehicle's history. This information will be lost, and there may be some performance issues with the vehicle until the computer relearns. This can take several driving cycles in order to effectively reboot the computer. OBD II vehicles that have theft-deterrent radios and/or car alarm systems may lose the pre-programmed information in the components. To retrieve and reset these components will require a visit to the dealership or contacting the manufacturer, and costs will be incurred.

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PCM Flash Reprogramming

Programming Your Car's Computer