Much like the operating system of a PC, the calibration files of Engine Control Module (ECM) are updated from time to time, to ensure ideal performance as the vehicle ages. These improvements, provided by the vehicle manufacturers, are often issues affecting fuel economy, driveability and diagnostics.

Before the introduction of flash technology, technicians would have to replace the entire ECM with one with an updated calibration. The only exception was General Motors, in which they designed their ECMs with removable PROMS (Programmable Read Only Memory), so a technician would only need to replace the PROM. Unfortunately, the location of the ECMs on the vehicle still required the technician to remove the module in order to replace the PROM.

With the introduction of flash technology the technician can simply update the ECM's calibration electrically, without removing the ECM from the vehicle or it's programmable memory. Currently every manufacturer has their own method, but generally it involves three components, OEM software & Data, a personal computer and a pass-thru device (either an OEM scan tool or an aftermarket interface like our 2534 Global Programmer).

1980

• Field programming is not available.
• Most manufacturers require the technician to replace the entire ECU for calibration updates.
• GM was the only OEM that had removable PROMs
  
  

1990

• First field programmable ECM with EEPROM is introduced for selective vehicles and with limited calibrations. OE tool is required for programming.
  
  

1993

• GM introduces first true pass thru "Flash" programming technology for selected vehicles with a larger amount of calibration selections, but again the OEM tool is required for programming.
  
  

1994

• Ford introduces first flash programmable vehicle, but the OEM tool is required for programming.
  
  

1995

• Chrysler introduces first flash programmable vehicle, but the OEM tool is required for programming.
  
  

1996

• All domestic OEM manufacturers design their ECMs/PCMs with flash technology.
  
  

2000

• September 2000 Bill SB1146 was passed in California. This bill mandates that all OEM manufacturers must make available to the aftermarket all the necessary information that is required to repair a vehicle. This includes service manuals, service bulletins, diagnostic materials and flash programming information.
  
  

2004

• Starting with model year 2004, OEM manufacturers that incorporate flash programming into their ECMs/PCMs are mandated by the EPA to make their systems comply with the SAE J2534 Standard.

The Environmental Protection Agency (EPA), who is responsible for the implementation of laws to control air pollution from motor vehicles, realized that vehicle emission is influenced by the Engine Control Module’s (ECM) calibration. Unfortunately, access to equipment to update the calibration that could improve vehicle emission was only available at dealerships.

Recognizing the importance of this issue, the EPA wanted the aftermarket to have the same ability to upgrade an ECM calibration. To accomplish this, the J2534 standard was created to standardize the methods between manufacturers.

The J2534 standard is made up of two interface specifications, an application programming interface (API) and a vehicle interface.

J2534 API

An Application Programming Interface (API) is an interface between OEM applications software and the Dynamic Link Library (DLL) for the J2534 Device.

Vehicle Interface

Working with the API is a vehicle interface that must be able to communicate with various vehicle protocols. The protocols specified in J2534 are ISO9141, J1850VPW/PWM, CAN, SCI SAE J2610 and KWP 2000.

OEM Software

A J2534 compliant device alone is not enough to reprogram an ECM. You will need to use the J2534 compliant application software from the car manufacturer. This application software can be delivered via the Internet or on a CD and will probably be a paid subscription.