406 Immobiliser problem

Hi, my N REG 406 diesel was working fine, i fitted a stereo and replaced
some fuses that were missing (now removed) and now the car asks for the
keycode to start (where it previously didn't). I've been told by the
previous owner the code is 1982, but the keypad denys it. Any idea's how
to get past this? Is there a service/ workshop code to get the thing
running again? thanks. james

 

Back to the garage where it was first bought,proof of ownership and they should
have it on books.Can't think of any other way but there must be one as I know of
firms who re-programme radios.Sometimes re-freezing the micro chip for 24hr
works in some electronic units.
"Texas Hold'em Poker"

"The bigger you bet,the less you win when you lose!"

 

If the keypad has a 68HC motorola MCU inside then this can be dumped and the
code read from there. You will need specific hardware and software to be
able to do this.

By far the easiest way is to read the 93C46/56 eeprom inside the ECU, there
are a few ECU's which have a micro, however most have eeproms. Simply read
the data from the chip with any compatible reader/programmer.

When you look through the dump you will see the code repeatead several times
(but reversed), for example:

0143 0143 0143 0143 is: 4301
1234 1234 1234 1234 is: 3412 and so on.

A new/virginised keypad will be supplied by your dealer. There aint no way
they'd even attempt any of the above!

Hope this helps.