toad c5 immobiliser malfunction in a 924
Printed From: the12volt.comForum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=114469
Printed Date: July 22, 2025 at 2:07 AM
Topic: toad c5 immobiliser malfunction in a 924
Posted By: dan kennard
Subject: toad c5 immobiliser malfunction in a 924
Date Posted: June 15, 2009 at 9:11 AM
Hi everyone. I'm having a problem with the Toad C5 immobiliser installed in my 1980 Porsche 924. The long and short of it is, whenever I close the bonnet, the alarm starts to repeatedly chirp very rapidly for about a minute or so, before slowly fading to silence.
The only maintenance I have done to the car was replacing the completely dead battery, and the nearside window motor. The C5 was working perfectly prior to this (well, prior to the battery running completely flat anyway).
If I remotely lock the doors before closing the bonnet, they remain locked, and the alarm will repeatedly chirp. I have to climb through the boot, and pop the bonnet catch before the C5 will let me disarm, and unlock the doors from the inside. After popping the bonnet, the alarm will sound normally, and I can then disable it with the dongle.
If I fail to enable the C5 before closing the bonnet, the alarm will also repeatedly and rapidly chirp, but the doors remain open. If I pop the bonnet, the alarm will sound normally again.
Before this morning, the last time I looked at the car was about a month and a half ago when I changed the battery. The only way I could stop the alarm was to put the old battery back in, but failing to connect the negative terminal. I thought I'd give it another look this morning (as I live away from home, and am currently visiting). I made sure the circuit was complete on the nearside door, and replaced the battery.
For a time, everything worked as normal. The problem only re-occurred after jump starting the car using a VW Golf. The minute I closed the bonnet after removing the jump cables, the chirping started again.
The strange thing is, if I leave the bonnet open, the C5 will function as normal. If I press and release the spring loaded alarm button, the alarm will sound as normal, and if I press down on it (simulating a closed bonnet), the chirping does not sound. It's only when I do actually close the bonnet, does the immobiliser stop responding, and the rapid chirping starts.
I wondered if there was a loose or trapped cable coming from the alarm unit, but I could only find one. And even then, I can't recall it actually ever being attached to anything (it's the looped white cable, with black insulation further down). The actual cable was exposed at the end slightly, but it was looped in on it's self and there no sign of it previously being soldered to anything:
Sorry about the poor pictures. The alarm was sounding loudly, and the neighbors started complaining, so I had to be quick.
I'm very much a car novice, but any ideas, help, or suggestions would be really appreciated.
Thanks for reading
-Dan
The only maintenance I have done to the car was replacing the completely dead battery, and the nearside window motor. The C5 was working perfectly prior to this (well, prior to the battery running completely flat anyway).
If I remotely lock the doors before closing the bonnet, they remain locked, and the alarm will repeatedly chirp. I have to climb through the boot, and pop the bonnet catch before the C5 will let me disarm, and unlock the doors from the inside. After popping the bonnet, the alarm will sound normally, and I can then disable it with the dongle.
If I fail to enable the C5 before closing the bonnet, the alarm will also repeatedly and rapidly chirp, but the doors remain open. If I pop the bonnet, the alarm will sound normally again.
Before this morning, the last time I looked at the car was about a month and a half ago when I changed the battery. The only way I could stop the alarm was to put the old battery back in, but failing to connect the negative terminal. I thought I'd give it another look this morning (as I live away from home, and am currently visiting). I made sure the circuit was complete on the nearside door, and replaced the battery.
For a time, everything worked as normal. The problem only re-occurred after jump starting the car using a VW Golf. The minute I closed the bonnet after removing the jump cables, the chirping started again.
The strange thing is, if I leave the bonnet open, the C5 will function as normal. If I press and release the spring loaded alarm button, the alarm will sound as normal, and if I press down on it (simulating a closed bonnet), the chirping does not sound. It's only when I do actually close the bonnet, does the immobiliser stop responding, and the rapid chirping starts.
I wondered if there was a loose or trapped cable coming from the alarm unit, but I could only find one. And even then, I can't recall it actually ever being attached to anything (it's the looped white cable, with black insulation further down). The actual cable was exposed at the end slightly, but it was looped in on it's self and there no sign of it previously being soldered to anything:
Sorry about the poor pictures. The alarm was sounding loudly, and the neighbors started complaining, so I had to be quick.
I'm very much a car novice, but any ideas, help, or suggestions would be really appreciated.
Thanks for reading
-Dan
Replies:
Posted By: howie ll
Date Posted: June 15, 2009 at 6:06 PM
Posted By: mikvot
Date Posted: June 15, 2009 at 6:10 PM
Posted By: howie ll
Date Posted: June 16, 2009 at 3:39 AM
Posted By: dan kennard
Date Posted: June 16, 2009 at 7:22 AM
Sorry, I should have said "hood" I guess 
I had a look at the hood switch, and the bolt on the underside had come loose. So I tightened it, and refitted the switch.
According to a wiring diagram for a similar Toad alarm (can't find one for the C5 though), a black wire close to the grey one connected to the hood switch is supposed to be ground.
The only black wire I could find was the partially stripped one shown in the 2nd photo above, with the bare end. As aforementioned it was loose, and I couldn't see any signs of it previously being soldered. Should I attempt to ground it? And if so, what would be the best ground source?
-Dan
I had a look at the hood switch, and the bolt on the underside had come loose. So I tightened it, and refitted the switch.
According to a wiring diagram for a similar Toad alarm (can't find one for the C5 though), a black wire close to the grey one connected to the hood switch is supposed to be ground.
The only black wire I could find was the partially stripped one shown in the 2nd photo above, with the bare end. As aforementioned it was loose, and I couldn't see any signs of it previously being soldered. Should I attempt to ground it? And if so, what would be the best ground source?
-Dan