Security Stytem/CPU #2 Issues
05-09-24, 09:48 AM
#1
Security Stytem/CPU #2 Issues
TL;DR. Headlights and Horn going crazy. Tried 2 different CPU#2s with no luck. Exhausted every fix my research has pointed me at with no luck.
OK, so I've dug through just about every CPU#2/Security system thread I can find, and I'm still stumped on this one. So the backstory here is, I did a bit of wiring over the winter on the car. I hooked up a Banzai Starter Booster, and wired up some LED lighting to turn signals and running lights to the factory wiring (de-pinned factory connectors to hook the new lights up, so everything would be plug and play). I also swapped out my CPU#2 for one from Tomsn16 to fix the stupid seatbelt flashing issue (I also did Dale Clark's flasher mod to the new(er) FD01 while I was in there) [Note: security relay has been bypassed long ago, but click click start issue persisted. Also, the HID headlights have been hooked up and working fine for over a year prior to this]. Hooked the battery back up, and everything was great for a few minutes. All lights worked as they should, and the no hyper flashing of the turn signals. Then, all of a sudden, the horn starts honking and the headlights come on. Unhook the battery for a few, then put it back on...horn going off immediately. Left it off over night, charge the battery, hook everything back up the next day. All is good.....for a few minutes. Horn/headlights again. Tried all the ways to disarm the system: Lock/unlock both doors with the key - Nothing (still going off). Unlock the trunk with key - Nothing. At this point, I take out the fuse for the horn, to at least let my family sleep while digging into this. I should also clarify, the hazards do not flash during this, nor do the headlights go up and down. They just stay up and on. The horn is also just constantly on as well. I never triggered the alarm before this, so I do not know if this is consistent with the alarm going off. I was always under the impression that the hazards go off, the horn beep beeps, and the headlights go up and down.
Tried old CPU#2. Same scenario. Tried all the same tests with the same result.
Unhook everything from CPU#2 (as per some of the old 'disable security system' threads. Ok. It's calm, so I can start to diagnose what's going on. I leave out the top 8-pin connector to try and save the wear and tear on my HIDs (as per this thread: https://www.rx7club.com/3rd-generati...n-off-1139269/). Plug in the bottom 7-pin. Still good. Plug in the 20-pin and I can immediately hear a feint electrical buzz on and off at CPU#2 (not quite like a relay clicking on and off, but something is happening and it is timed perfectly with the security light on the console and the little light at the ignition) [Note on this subject: I would also later see the flashing of the driver door lock light was also in-time with this click as well]. I can stop the security light from flashing by putting the key in the ignition, but the click from cpu#2 remained, even with ignition on. I then tried to actually arm the security system from the drivers door lock. Armed as usual, and I get the "beep beep" noise to confirm. CPU#2 click persisting. Unlock the door with key from the outside, and everything keeps flashing and clicking. I also noticed that I can arm the security system with either the trunk or hood open (even tried it with both open), and from the research I did, that doesn't seem like it should be possible (so I think the fix of grounding out the hood/hatch sensors won't work in this scenario).
I have a new CPU#2 ordered, but I am worried that something else is wrong that is causing the issue, and I don't want to fry and very expensive, brand new, cpu#2, so I'm trying to figure out the underlying issue. I think my issue is slightly different from Jose A's (linked above), as his seemed to just be headlight related, while mine is also the horn. My issue also seems similar to this thread: https://www.rx7club.com/3rd-generati...pairs-1161468/ but mine does not seem to cause the window to hesitate in this way (mine went straight down), and his seems intermittent and temperature dependent. My issue started over the winter and has persisted into some 70-80 deg days.
With the top 8-pin connector out and the 20-pin connector plugged in, I seem to have full control over everything (although I haven't put the horn fuse back in yet to test if that still works), but the buzz/click from CPU#2 is there, so I think that will be a constant drain on the battery. The only thing I can think to do at this point is to ring out each wire on the 20-pin connector, as something on that connector seems to be the root of the issue. And from the FSM, it looks like only 9 of those are associated with the security system. I don't think it would be possible to leave this unplugged for an extended period of time either, as this has things like the TNS relay and ignition switch on the circuit. So I don't even know if the car will function without it plugged in.
Any input would be appreciated. Or if there is something that I'm missing. I don't THINK any of the wiring changes I did over the winter should cause this, but I've been wrong before......and the fact that everything was fine (except for the flashing seatbelt light) before doing all this....well, it kinda points to me messing SOMETHING up over the winter. I just can't track down what it would have been. *EDIT* I'll also add, I disconnected the lower 7 pin connector to the cpu, and I still had the on/off clicking sound continue. So, since the turn signals are on that connector, I THINK this should confirm that the modifications I did to the turn signals/running lights should not be the issue. I could be wrong though.
OK, so I've dug through just about every CPU#2/Security system thread I can find, and I'm still stumped on this one. So the backstory here is, I did a bit of wiring over the winter on the car. I hooked up a Banzai Starter Booster, and wired up some LED lighting to turn signals and running lights to the factory wiring (de-pinned factory connectors to hook the new lights up, so everything would be plug and play). I also swapped out my CPU#2 for one from Tomsn16 to fix the stupid seatbelt flashing issue (I also did Dale Clark's flasher mod to the new(er) FD01 while I was in there) [Note: security relay has been bypassed long ago, but click click start issue persisted. Also, the HID headlights have been hooked up and working fine for over a year prior to this]. Hooked the battery back up, and everything was great for a few minutes. All lights worked as they should, and the no hyper flashing of the turn signals. Then, all of a sudden, the horn starts honking and the headlights come on. Unhook the battery for a few, then put it back on...horn going off immediately. Left it off over night, charge the battery, hook everything back up the next day. All is good.....for a few minutes. Horn/headlights again. Tried all the ways to disarm the system: Lock/unlock both doors with the key - Nothing (still going off). Unlock the trunk with key - Nothing. At this point, I take out the fuse for the horn, to at least let my family sleep while digging into this. I should also clarify, the hazards do not flash during this, nor do the headlights go up and down. They just stay up and on. The horn is also just constantly on as well. I never triggered the alarm before this, so I do not know if this is consistent with the alarm going off. I was always under the impression that the hazards go off, the horn beep beeps, and the headlights go up and down.
Tried old CPU#2. Same scenario. Tried all the same tests with the same result.
Unhook everything from CPU#2 (as per some of the old 'disable security system' threads. Ok. It's calm, so I can start to diagnose what's going on. I leave out the top 8-pin connector to try and save the wear and tear on my HIDs (as per this thread: https://www.rx7club.com/3rd-generati...n-off-1139269/). Plug in the bottom 7-pin. Still good. Plug in the 20-pin and I can immediately hear a feint electrical buzz on and off at CPU#2 (not quite like a relay clicking on and off, but something is happening and it is timed perfectly with the security light on the console and the little light at the ignition) [Note on this subject: I would also later see the flashing of the driver door lock light was also in-time with this click as well]. I can stop the security light from flashing by putting the key in the ignition, but the click from cpu#2 remained, even with ignition on. I then tried to actually arm the security system from the drivers door lock. Armed as usual, and I get the "beep beep" noise to confirm. CPU#2 click persisting. Unlock the door with key from the outside, and everything keeps flashing and clicking. I also noticed that I can arm the security system with either the trunk or hood open (even tried it with both open), and from the research I did, that doesn't seem like it should be possible (so I think the fix of grounding out the hood/hatch sensors won't work in this scenario).
I have a new CPU#2 ordered, but I am worried that something else is wrong that is causing the issue, and I don't want to fry and very expensive, brand new, cpu#2, so I'm trying to figure out the underlying issue. I think my issue is slightly different from Jose A's (linked above), as his seemed to just be headlight related, while mine is also the horn. My issue also seems similar to this thread: https://www.rx7club.com/3rd-generati...pairs-1161468/ but mine does not seem to cause the window to hesitate in this way (mine went straight down), and his seems intermittent and temperature dependent. My issue started over the winter and has persisted into some 70-80 deg days.
With the top 8-pin connector out and the 20-pin connector plugged in, I seem to have full control over everything (although I haven't put the horn fuse back in yet to test if that still works), but the buzz/click from CPU#2 is there, so I think that will be a constant drain on the battery. The only thing I can think to do at this point is to ring out each wire on the 20-pin connector, as something on that connector seems to be the root of the issue. And from the FSM, it looks like only 9 of those are associated with the security system. I don't think it would be possible to leave this unplugged for an extended period of time either, as this has things like the TNS relay and ignition switch on the circuit. So I don't even know if the car will function without it plugged in.
Any input would be appreciated. Or if there is something that I'm missing. I don't THINK any of the wiring changes I did over the winter should cause this, but I've been wrong before......and the fact that everything was fine (except for the flashing seatbelt light) before doing all this....well, it kinda points to me messing SOMETHING up over the winter. I just can't track down what it would have been. *EDIT* I'll also add, I disconnected the lower 7 pin connector to the cpu, and I still had the on/off clicking sound continue. So, since the turn signals are on that connector, I THINK this should confirm that the modifications I did to the turn signals/running lights should not be the issue. I could be wrong though.
Last edited by REnaissance_Sle7in; 05-09-24 at 01:39 PM.
05-10-24, 08:01 AM
#3
Two different CPU2 with the same issues: I think the issue isn’t the CPU. You’re on the right track with troubleshooting. In the Body Electrical troubleshooting FSM around section J2 is a great diagram showing all the security system connections to CPU2. Probably need to depin them one at a time until the car acts normal then troubleshoot the line causing the alarm to go off.
Matt
Matt
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REnaissance_Sle7in (05-10-24)
05-10-24, 08:38 AM
#4
Well, now I'm even more confused. I ended up putting the CPU#2 I modified from Carter back into the car (I figured if I was going to have these issues anyway, may as well not have hyper flashing turn signals). Plugged it in....and bam, no issues. WTF. The ONLY thing that I was able to find was a ground for one of the turn signals was giving an intermittent signal. I was noticing lights flickering when the turn signal was on, which lead me to it. I had assumed that since I was able to use the turn signals, and those are both on the 7-pin connector, that circuit was good. But the 'hazard' is on the 20-pin, so maybe that was my issue
I still don't trust that its gone. Could have just been luck and the issue is still intermittent. I will report back if I find anything else for prosperity sake.
I'll also note that I can still arm the alarm system with the hood and/or trunk open....so something is still strange, but for now, I'm taking the W. I've missed like 3 weeks of nice weather already.
05-10-24, 08:44 AM
#5
Two different CPU2 with the same issues: I think the issue isn’t the CPU. You’re on the right track with troubleshooting. In the Body Electrical troubleshooting FSM around section J2 is a great diagram showing all the security system connections to CPU2. Probably need to depin them one at a time until the car acts normal then troubleshoot the line causing the alarm to go off.
Matt
Matt
05-10-24, 10:03 AM
#7
Ban Peak
iTrader: (49)
Weird question but do you park the car inside or outside?
I don't have my wiring books with me but my immediate thoughts are to check the hood latch switch (the microswitch mounted to it for the security system) and the relay box that gets relocated with the V Mount kit. If you had the car outside you could have a problem presenting itself that is unrelated to your work due to water intrusion.
I don't have my wiring books with me but my immediate thoughts are to check the hood latch switch (the microswitch mounted to it for the security system) and the relay box that gets relocated with the V Mount kit. If you had the car outside you could have a problem presenting itself that is unrelated to your work due to water intrusion.
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05-10-24, 11:00 AM
#9
Weird question but do you park the car inside or outside?
I don't have my wiring books with me but my immediate thoughts are to check the hood latch switch (the microswitch mounted to it for the security system) and the relay box that gets relocated with the V Mount kit. If you had the car outside you could have a problem presenting itself that is unrelated to your work due to water intrusion.
I don't have my wiring books with me but my immediate thoughts are to check the hood latch switch (the microswitch mounted to it for the security system) and the relay box that gets relocated with the V Mount kit. If you had the car outside you could have a problem presenting itself that is unrelated to your work due to water intrusion.
No worries. And I see they are there now, and those are great ones to have on the FAQ. Particularly Gen2n3's component list one. As these CPUs get more and more expensive, that is going to be a very viable way forward with this item.
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