Immobilizer died on my lift
09-25-2016, 11:24 PM
#1
Rennlist Member
Thread Starter
Immobilizer died on my lift
It probably couldn't have happened at a better location but my immobilizer finally quit. Fortunately the doors were unlocked. I have a 1996 C4S that was stored on top and only driven about once a month. I lowered the lift last week to drive the car and no response. Here are the details.
1) Doors will not lock or unlock; no response to key fob
2) Door lock button in the car still functions correctly
3) Battery fully charged; stays on trickle charger
4) Primary nor backup key fob don't work; just for cheap insurance, I changed the battery in one of them and still nothing
5) With key in position one, immobilizer light on the dash goes out after 2 seconds just like manual says but then comes back on and stays on after another few seconds; I assume this is what the manual means when it says the light flashes to indicate immobilizer failure. Information light is also lit.
I've read the many writeups and looked at a few Youtube videos but I'd like to confirm just what I need to pull and send in for repair? Do I send in the Immobilizer board and ECU or just the immobilizer? I assume I need to also send in both key fobs?
1) Doors will not lock or unlock; no response to key fob
2) Door lock button in the car still functions correctly
3) Battery fully charged; stays on trickle charger
4) Primary nor backup key fob don't work; just for cheap insurance, I changed the battery in one of them and still nothing
5) With key in position one, immobilizer light on the dash goes out after 2 seconds just like manual says but then comes back on and stays on after another few seconds; I assume this is what the manual means when it says the light flashes to indicate immobilizer failure. Information light is also lit.
I've read the many writeups and looked at a few Youtube videos but I'd like to confirm just what I need to pull and send in for repair? Do I send in the Immobilizer board and ECU or just the immobilizer? I assume I need to also send in both key fobs?
Last edited by autobonrun; 09-26-2016 at 05:42 PM.
09-26-2016, 12:08 AM
#2
Burning Brakes
Can't provide you any help on sorting out your Immobilizer. However, have you considered having the immobilizer deactivated permanently? To do this, you'll need to send your ECU into someone like ECU Doctors (in Florida), and they will deactivate the immobilizer. Reinstall the ECU and the car will start without any lockout from the immobilizer.
Though the immobilizer will be deactivated, you will get a blinking immobilizer light in the clock. It's the immobilizer in the car looking for the ECU. Can't find it, so the light blinks.
To cure the blinking light, some folks just remove the bulb from the clock. Or, you can pull the starter motor relay out of the relay box (in the trunk) and replace the relay with a shorting strip made to bypass the starter.
Your key fob will continue to be functional for door locks; but, not for any other function. So, you won't need to ever again hit the fob button before you can start the car.
I deactivated my immobilizer two years ago, and am thankful that I did. Really hated the thing!
Though the immobilizer will be deactivated, you will get a blinking immobilizer light in the clock. It's the immobilizer in the car looking for the ECU. Can't find it, so the light blinks.
To cure the blinking light, some folks just remove the bulb from the clock. Or, you can pull the starter motor relay out of the relay box (in the trunk) and replace the relay with a shorting strip made to bypass the starter.
Your key fob will continue to be functional for door locks; but, not for any other function. So, you won't need to ever again hit the fob button before you can start the car.
I deactivated my immobilizer two years ago, and am thankful that I did. Really hated the thing!
09-26-2016, 08:52 AM
#3
Rennlist Member
Thread Starter
Can't provide you any help on sorting out your Immobilizer. However, have you considered having the immobilizer deactivated permanently? To do this, you'll need to send your ECU into someone like ECU Doctors (in Florida), and they will deactivate the immobilizer. Reinstall the ECU and the car will start without any lockout from the immobilizer.
Though the immobilizer will be deactivated, you will get a blinking immobilizer light in the clock. It's the immobilizer in the car looking for the ECU. Can't find it, so the light blinks.
To cure the blinking light, some folks just remove the bulb from the clock. Or, you can pull the starter motor relay out of the relay box (in the trunk) and replace the relay with a shorting strip made to bypass the starter.
Your key fob will continue to be functional for door locks; but, not for any other function. So, you won't need to ever again hit the fob button before you can start the car.
I deactivated my immobilizer two years ago, and am thankful that I did. Really hated the thing!
Though the immobilizer will be deactivated, you will get a blinking immobilizer light in the clock. It's the immobilizer in the car looking for the ECU. Can't find it, so the light blinks.
To cure the blinking light, some folks just remove the bulb from the clock. Or, you can pull the starter motor relay out of the relay box (in the trunk) and replace the relay with a shorting strip made to bypass the starter.
Your key fob will continue to be functional for door locks; but, not for any other function. So, you won't need to ever again hit the fob button before you can start the car.
I deactivated my immobilizer two years ago, and am thankful that I did. Really hated the thing!
09-26-2016, 09:06 AM
#4
RL Community Team
Rennlist Member
Rennlist Member
Your problem may be simpler than you think, clean the fob battery contacts and bend them if needed for good connection. The batteries you used as replacements may have been weak or dead old stock at the retailer. If the flashing led on the door sills flashes in couplets you have a door, lid or glove compartment switch or bulb issue.
09-26-2016, 02:56 PM
#5
Rennlist Member
Thread Starter
Your problem may be simpler than you think, clean the fob battery contacts and bend them if needed for good connection. The batteries you used as replacements may have been weak or dead old stock at the retailer. If the flashing led on the door sills flashes in couplets you have a door, lid or glove compartment switch or bulb issue.
I spoke with ECU doctor and got some advice on removing the pieces. It looks like both seats will have to come out. The good news for me is they also replace the antenna. Even when my fobs worked, the range was measured in inches rather than feet so hopefully this fix cover everything and it will last another 20 years.
09-26-2016, 03:58 PM
#6
RL Community Team
Rennlist Member
Rennlist Member
No flashing unless the system is active. If it originally only worked from a few inches this is unusual and suggests the antenna wire or its connection is iffy. I seem to recall seeing the wire behind the driver A pillar inside vinyl wrap. If the antenna is shorted to ground it will not receive a signal. Before ripping things apart trace the antenna wire or just put a new wire in its place to the control box and see what happens.
With fresh batteries my fob works from about four or five feet from the car. As the fob battery ages it works from as little as one foot before I replace the battery.
Good luck with this!
With fresh batteries my fob works from about four or five feet from the car. As the fob battery ages it works from as little as one foot before I replace the battery.
Good luck with this!
09-26-2016, 04:25 PM
#7
Rennlist Member
Thread Starter
No flashing unless the system is active. If it originally only worked from a few inches this is unusual and suggests the antenna wire or its connection is iffy. I seem to recall seeing the wire behind the driver A pillar inside vinyl wrap. If the antenna is shorted to ground it will not receive a signal. Before ripping things apart trace the antenna wire or just put a new wire in its place to the control box and see what happens.
With fresh batteries my fob works from about four or five feet from the car. As the fob battery ages it works from as little as one foot before I replace the battery.
Good luck with this!
With fresh batteries my fob works from about four or five feet from the car. As the fob battery ages it works from as little as one foot before I replace the battery.
Good luck with this!
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09-27-2016, 05:39 PM
#8
RL Community Team
Rennlist Member
Rennlist Member
it is just a wire, nothing high tech.
10-25-2016, 09:34 AM
#9
Rennlist Member
Thread Starter
Just for closure, the problem ended up being in the immobilizer module. Capacitors had opened and the solder tracks on the circuit boards had cracked from age. ECUdoctors did a great job and were easy to work with. My key fobs which had to be within 6 inches of the car to work now function from 20 feet.
Initially when I reinstalled the ECU and immobilizer back in the car, it would stall when I depressed the clutch at a light. I found out the ECU needed to relearn it's adaptation maps, especially with my LWF. After two days of driving, it seems to have learned because there is no more stalling. RPMs now drop slower when the clutch is depressed than on the first day; it would drop like a rock when I first reinstalled the ECU and immobilizer.
Anyway, I'm driving it to work for a few days to give it even more time to adapt. I seldom drive to work; some are getting to see my 993 for the first time but I want to put some miles on the repair.
Initially when I reinstalled the ECU and immobilizer back in the car, it would stall when I depressed the clutch at a light. I found out the ECU needed to relearn it's adaptation maps, especially with my LWF. After two days of driving, it seems to have learned because there is no more stalling. RPMs now drop slower when the clutch is depressed than on the first day; it would drop like a rock when I first reinstalled the ECU and immobilizer.
Anyway, I'm driving it to work for a few days to give it even more time to adapt. I seldom drive to work; some are getting to see my 993 for the first time but I want to put some miles on the repair.
10-25-2016, 01:58 PM
#10
RL Community Team
Rennlist Member
Rennlist Member
10-26-2016, 07:25 PM
#11
Burning Brakes
It's a mute point now that you have gotten your immobilizer fixed by ECU Doctors. But, to deactivate the immobilizer does not require any work on the immobilizer module which resides next to the ECU under the front seats. You just abandon the module in place and have the ECU modified to delete the immobilizer. And, in my 98 car, both the ECU and immobilizer module were located under the driver's seat, so both seats did not have be pulled. My car is fitted with the hifi option which places an amplifier under the passenger seat, leaving no room for the immobilizer module, which may be the reason mine is moved to under the driver seat.
10-27-2016, 01:37 PM
#12
as the source of the real problem. As mentioned up-thread, it could have been
poor connections that eventually were resolved by the various removal and re-connection
of the alarm/immobilizer system elements.
Last edited by Lorenfb; 10-27-2016 at 01:55 PM.