Methods of Remapping
All petrol cars sold within Europe since 1st Jan 2001 and all diesel cars manufactured from 2003 must have OBD (On-Board Diagnostic) systems to monitor engine emissions. Although, OBD systems have been fitted to many vehicles since the early 1990s. These systems were introduced in line with the European Directive 98/69/EC to monitor and reduce emissions from cars. OBD equipped vehicles are also fitted with an OBD port. This port is basically a communication port, designed to allow diagnostic equipment to interrogate and even reprogram the ECUs fitted to a vehicle. The introduction of the OBD port completely transformed the way tuners accessed the map data stored inside ECUs.
Remapping through the OBD port is the most efficient and non-intrusive tuning method. It allows us to achieve some amazing results without even opening the bonnet. Using specialist equipment, the data can be extracted from the ECU via the OBD port. Once the data has been modified, the data can then be reapplied to the ECU using the same process.
Remapping a vehicle through its OBD port is not always possible for various reasons. The vehicle may not have an OBD port, the port may be faulty or the ECU may be ‘tune protected’ (systems put into place by the manufacturer to prevent ECU data from being modified via the OBD port). Bench tuning is the nickname given to the process of removing the ECU from a vehicle and making a direct connection to the internal circuit board of the ECU on the “work bench”. There are several different methods of communicating with the ECU and the method used depends on the type of ECU and the internal microprocessor.
BDM or Background Debug Mode is the process of connecting directly to the circuit board of an ECU, using a specially engineered jig to hold the ECU in place while data pins are connected to the circuitry. Other methods include: Boot Mode, Pin Out, JTAG etc.
Chip Tuning – ‘Chipping’
Early ECU systems contained EEPROMs (AKA Chips,) which stored the map data. To read the data programmed to these chips, tuners often de-solder the chip from the board and place the chip in a chip reader. This data would then be modified and reloaded on to the chip. However, the chips fitted to some early ECU’s were often OTP (One Time Programmable) meaning that although the data could be extracted from the chip, the new modified map data could not be programmed back onto the same chip. To overcome this, the tuner will program a new chip with the modified data and solder the new chip to the circuit board. This process is often nicknamed ‘chip change’.
Since the introduction of multi programmable chips and MCUs, tuners have adopted faster, cleaner and less detectable methods of remapping i.e. OBD and BDM tuning. Although it must be noted that there are still many cars on the road today that have to be chip tuned.
Although these processes are very different, they are all methods for remapping.
We hope you have found some of this information useful and now have a better understanding of what remapping involves and how electronic tuning can alter the performances and characteristics of a vehicle.