Auto Electronic

Why a Battery Support Unit is important for Engine ECU remapping?

CTEK pro 25s

What is Engine ECU Remapping

Engine ECU remapping is a process of modifying the car’s onboard computer (often called an Electronic Control Unit, or ECU) with new software to affect its behaviour. The ECU usually limits the engine ECU’s performance to improve reliability, emissions, and fuel consumption. A remap is usually done to unlock more power from an engine ECU by removing some of these restrictions. It’s also possible to have a remap focused on increasing fuel consumption as well ¹.

The process of engine ECU remapping is relatively simple and is usually done by plugging a laptop into the car’s OBD port ¹. However, it’s not quite as simple as downloading the software online and doing it yourself. You’ll need to hand your car over to a trained professional, though some companies do offer a DIY service ¹.

The benefits of engine ECU remapping include low-cost improvement of your car’s performance, no need to upgrade any physical aspect of your car to get the performance benefits of a remap, and it’s usually reversible ¹. However, it usually invalidates a car’s warranty, which is an alteration of the car after all, which could affect the reliability of your engine ECU beyond the manufacturer’s control ¹.

What is a Battery Support Unit?

A battery support unit is a device that helps maintain the right voltage in the vehicle battery during the remapping, flashing or diagnosis process. Engine ECU remapping drains a lot of energy from the vehicle and if the battery dies or the voltage fluctuates during the process it can damage the vehicle CPU or cause to restart the process causing loss of time and money.

CTEK Pro 25s the perfect companion to ECU remapping process

What are the tools needed for engine ECU remapping?

  • A medium-spec Laptop
  • An OBD Tool with the right cable as per the vehicle OBD port
  • An engine ECU remapping device
  • A Battery support unit


A medium-range laptop with medium specs as seen in office work will suffice for the job. However, a high-end laptop with gaming specs will ensure faster and more accurate mapping.

An OBD tool

The OBD tool like Foxwell i70 Pro is required to ensure that before the engine ECU remapping process starts underlying issues in the vehicle electronics are identified and rectified. This will ensure the desired results are achieved and no surprises occur later.

An Engine ECU Remapping device

This is the heart of the process. An engine ECU remapping device helps to connect the laptop with the engine ECU and then allows to make changes. The main reason drivers get their engine ECU remapped is to boost a car’s speed and power. But car engine ECU remapping can bring other benefits:

Better fuel economy

If you go easy on the accelerator, remapping could help to increase your car’s mile per gallon (mpg) and overall fuel economy by optimising how much fuel is burned. You could save money and reduce your carbon footprint.

Better control and driveability

With an enhanced throttle and faster engine ECU response, as you press the accelerator (high torque), your car may feel smoother and easier to drive. You’ll have greater confidence when overtaking too.

A Battery Support Unit

During the ECU Remapping process, the vehicle draws energy for the battery and the voltage starts to drop. This leads to the risk of incomplete remapping with a serious impact on the vehicle and might lead to the changing of the ECU altogether. It is advised to maintain the voltage at around 14v, and not let it drop below 12.7V. Advanced chargers like CTEK Pro 25s have a supply function that enables the battery to have a robust voltage and complete the work with ease.

Use the following video to understand how to set up the vehicle before the remapping process.