1995 Mitsubishi Mirage 4g93 ECU

- Basic demonstration of an EPROM Mitsubishi ECU -


Mitsubishi Part: MD302726

ECU Code: E2T300902

EPROM Chip: EB13 & EB13a

Socketed by Patrick (Dude in a Mirage)


(Click on Images to view a the larger 1024x768 version of each)

Unsocketed/untouched EPROM chip - and a socketed ECU board

(the chips are soldered to the board by Mitsubishi)

OEM unsocketed EB13 ECU boardSocketed EB13 ECU board

ZIF Socketed ECU board (easier for chip changes)

ZIF Socketed EB13a EPROM ECU MD302726 - E2T300902 ECU with a ZIF socket

Leaking Capacitor Damage

Relatively common and you should check for it before the board is ruined

Leaking Capacitor on a Mitsubishi ECU Board

A helpful post on the DSM-ECU Yahoo group regarding code addresses:

Posted by: "Steve Piette" Fri Jun 27, 2008 on the Yahoo Group "DSM-ECU"


There is no difference between the 16k and 32k EPROM images when it comes to the actual software. The difference is that the 32k image has 16k of padding in front the code or two copies of the image depending on the size of the original EPROM and how the image was made.

The sooner we get people to start working in memory address mode rather than EPROM offset addresses the less confusing it will be. The real code lives in the address space starting at 0xc000 (c000h) to 0xffff.

The 16k images are 0x4000 (0x0000 to 0x3fff) long and need 0xc000 added to each location to get the memory address. The 32k images are 0x8000 (0x0000 to 0x7fff) long and need 0x8000 added to each location to get the memory address.

So for example the rev limiter parameter in the E931 code is at 0xf27a, which is 0x727a bytes from the beginning of a 32k image or 0x327a bytes from the beginning of a 16k image.

0xf27a - 0xc000 = 0x327a
0xf27a - 0x8000 = 0x727a

You'll also hear 0xc000 and 0x8000 referred to as the EPROM offset.


The reason you need a 512k chip to save a 64k ECU file is this: The code is 32 or 64 kilobytes and the chips are 256 or 512 kilobits (64 * 8 = 512 kilobits)


Screen Prints are from Tuner Pro

Stock EB13 Fuel Table #1

Stock EB13 Fuel Table #2

Stock EB13 Ignition Timing Table #1 (there are five of them)

Stock EB13 Ignition Timing Table #2

Stock EB13 Ignition Timing Table #3

Stock EB13 Ignition Timing Table #4

Stock EB13 Ignition Timing Table #5

There are usually a few fuel maps and more timing maps in the ECU code. The two fuel maps on US cars are for Federal or California emmisions. There are resistors on the board that designate whch the ECU will use, thus making it a Federal or California emmisions ECU.


The only tuning difference between a EB13 and EB13a chip is Timing Table 3. Most US 1995 4g93 Mirages use Timing Table 2.

Here is the comparison table so you can see the difference:

Stock EB13a Ignition Timing Table #3


Stock chip is a 27C256-12 (UV erasable) 256k chip
Standard replacement is 27C512 (PLCC 32) 512k chip
Electronically erasable is SST27SF512 (PLCC 32) 512k chip

They are 28-pin chips

If you are using a 512k chip, the code has to be on the last 256k of the chip. The easiest way to do this is to get the code ready, then copy the entire 256k of code, and paste it onto the end. It will always fill exactly 256k and your code is just on the chip twice.


You can order chips from here:


You are looking for C2 SST 27SF512 Chips

I am currently using the Moates Burn1 chip burner to erase and write to the chips and am very happy with it