1996 993 Carrera Battery Replacement
03-15-2019, 09:03 PM
#1
2nd Gear
Thread Starter
Join Date: Mar 2019
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
1996 993 Carrera Battery Replacement
I am having problems reseting the immobilizer & alarm system after replacing the battery in my 1996 993 Carrea. The remote control key fobs both work to lock & unloct the car. I could also successfully enter the radio code. I unlocked the car (red light on doors went off), got into the car, quickly inserted the ignition key ( in less than 10 seconds) and the instrument lights came on, the horn sounded and the starter would not start. I carefully followed the procedures within th owners manual. Now when I turn the key in the ignition within 10 seconds the instruments lights all come on, the horn sounds and the engine successfully starts but the horn still sounds. Please send me any suggestions and/or instructions or a video source for correcting these issues.
03-17-2019, 07:56 PM
#4
Rennlist Member
Very confusing post and symptoms - don’t remember seeing this before. What made you think you had to reprogram the remotes after a battery swap? The only thing you would have lost is the four digit radio code.
In any any case I agree, try disconnecting the battery for a few minutes. Most of us just leave the electric bus on the maintainer while doing a battery swap.
In any any case I agree, try disconnecting the battery for a few minutes. Most of us just leave the electric bus on the maintainer while doing a battery swap.
03-17-2019, 08:30 PM
#5
2nd Gear
Thread Starter
Join Date: Mar 2019
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Both key fobs successfully lock (arm the alarm & immobilizer) red door lights flash on & off, on & off for about 10seconds then start consistent blink, space, blink, space and unlock the doors (red door lights go out, can open the doors without setting off the alarm. I followed one memebers suggestion to lock the doors, wait for the constantly blinking red door lights to change to blink, space, blink. Then to unlock the doors and insert the key and start the car within 10 seconds. When I turned the ignition key on the horn sounds, all lights on the instruments continuously flash on & off, on & off while the car starts and idles. I have to turn off the ignition to stop the horn and blinking lights. Very strange. I will try disconnecting the car battery tomorrow. Wait for while, reconnect the battery, use the key fobs to lock & unlock the doors and try to start the car.
03-17-2019, 09:06 PM
#6
Rennlist Member
What?
03-18-2019, 12:10 AM
#7
Rennlist Member
Got it. I think. I’m stumped - never seen a post like this with this behavior in 17 years on the 993 forum. Did you do anything else electrically besides the battery change? Check your grounding strap just for the heck of it - the lit up dash makes me think intermittent ground path but can’t explain the horn.
Trending Topics
03-18-2019, 05:02 AM
#8
Rennlist Member
I guess this is a problem with the alarm/door lock control unit. If the doors unlock and the alarm is shut off (allows starting the engine) and still the alarm horn sounds, there must be an internal problem in the control unit. I would guess a faulty horn relay or horn relay driver circuit, or maybe the microprocessor itself. Such faults can occur if there has been disturbances in the power supply, maybe a voltage spike when disconnecting/connecting the battery.
The easiest way forward could be to disconnect the horn, and get the alarm/door lock control unit checked/repaired. Disconnecting the alarm/door lock control unit will remove the power supply to the engine control unit.
Cheers,
Tore
The easiest way forward could be to disconnect the horn, and get the alarm/door lock control unit checked/repaired. Disconnecting the alarm/door lock control unit will remove the power supply to the engine control unit.
Cheers,
Tore
