corsa b immobiliser ..anyway to bypass??

[leaky196]

friend of mine has a 99 corsa b 1.2 16v.

has an intermitant fault with the immobiliser.

few times a day the em light flashes and the car wont start.

now i know its the immo kicking in..but then all of a sudden it will work fine and she can start up and drive off.

now is there any way to bypass the immob??

..or do is it a case of finding another ecu chip and transponder ??

cheers

[Paul]

Cannot be bypassed.

Got a spare key to try?

[leaky196]

no mate..she only got one key with the car.ive tried to tape the chip to the transponder..but still plays up every now and then

[Paul]

Worth asking Vauxhall on a price on a key, but i'd probably just swap the ECU etc.

[leaky196]

Worth asking Vauxhall on a price on a key, but i'd probably just swap the ECU etc.

ok mate..thanks for the advice

[leaky196]

right..changed ecu,transponder and chip from a known working car...car fired and worked ok for a few hours...now wont start again..

em light flashing all the time.

any ideas please..apart from gallon of petrol and a match

[wkdkris]

make sure the old chip is no where near it, try flashing the codes to see what ECU says is the prob

[corsakristian]

yeah check the codes is your best bet

[leaky196]

how do i check the codes then?

this is new to me

[Paul]

Fault code reader I think is needed on these.

Have a search though for paper clip test

[leaky196]

cheers..got a neighbour who has one..will get him to try it.

any other ideas if nothing comes up in fault codes...as no em light on at any time.?

[Dom]

Try having the ignition key on a seperate keyring and have it as the only key on it. You may find other keys interfere - worth a try just to eliminate this.

[leaky196]

Try having the ignition key on a seperate keyring and have it as the only key on it. You may find other keys interfere - worth a try just to eliminate this.

already done that mate..key is all on its own.

[Dom]

Next port of call would be to check all wiring between the immobiliser ring and the ECU - check pins for corrosion. If the two don't talk properly then you'll get this problem.

This is the only other thing I can think it could be.

[wkdkris]

99...... 16 pin plug???? on the left hand side of the dianostics plug, 1 blank, 1 metal, miss, so 2 down... short the next 2 with a paper clip and put ignition on, itl flash the codes.....eml flashing while trying to start will log a immob code, no comm, incorrect signal etc etc

[MSG]

as per what Dom suggested, you could be having a problem with a bad wiring connector, so check all wiring between the ignition collar ring is soldered good to its pcb and then from this pcb wiring link to your ECU.

[leaky196]

right..these are the 2 codes that came up today.

P1502 immobiliser error
P1503 immobiliser signal error

now when the codes where cleared...we got the car started....let it run for a few min.

turned it off..em light flashing again...so re scanned it...only one code came back.

p1502 immobiliser error

[corsakristian]

check your fuses mate just to make sure its not them as sometimes they can cause daft stuff like this. Also have you tried leaving the battery disconnected for half an hour to reset the ecu? that might just do the trick

[leaky196]

check your fuses mate just to make sure its not them as sometimes they can cause daft stuff like this. Also have you tried leaving the battery disconnected for half an hour to reset the ecu? that might just do the trick

done all of those things mate..thats why its doing my head in..if i take battery off..it works for a while..then goes back to em flashing

[leaky196]

any other ideas..this like a needle in a haystack

[MSG]

The codes are really helpfull arn't they.....what does immobiliser error tells us ...we already know the ****in thing is not working, why can't it be more specific and tell us that there is a problem with a digri doo.

Any ways, many people ask if modern immobiliser can be Bypassed, the answer is absolutely Not, the designers of immobiliser bore in mind that thieves could also bypass it to steal, hence they embedded part of the security codes inside the chips used for controlling engine strating functions and smooth running of it, so if anyone tried bypassing security would fail miserably, however, there are still ways to steal a car, wire up an aftermarket engine management and off you go, simply hook up ignition coil or DIS pack and crank sensor, as well as the MAF sensor to an aftermarket EM, and need not wire other sensors such as temperature or oxygen sensor and you could start an engine and drive off, though it may run poorly without all sensors wired in.

If you have already tried another ecu and corresponding transponder chip, and is still failing, you ought top look at the little circuit under the ignition collar sensing coil, did you change that circuit as well? If not this is where your problem may lie.

[leaky196]

if you meen the transponder..then yes mate..i got a complete lot..ecu..chip and transponder.

[leaky196]

ive put wd 40 on most connections..made sure they are corrosion free..

tried fuses..relays.etc...and still the f'ing thing chucks a paddy.

if i disconnect the battery for awhile..it starts up straight away...
but turn it off....and the em light flashes again

time to burn it??

any other ideas fella..?

[wkdkris]

wiring if youve changed EVERYTHING involved... hasnt got an alarm has it? whats immobing it?

[lee303]

where is the transponder pick up ring? usual place? or just in the vicinity? they are very sensitive to the transponder going out of range