I have had a post on this, but just wanted to start a new one since i have done some work. Still need help....

First, the codes:
P1631 H
B2721 H
B2723 H

Awhile after buying my 03 AE, I started getting the SECURITY light. MOST of the time it would come on as I am driving down the road. Every once in awhile though, it would come on as soon as I start the car. During this time, it has not started on me 4 times. I would get the gauge sweep and the electronics would work, but it would not even attempt to start when I would turn the key. I started researching this forum and the net to try and find a possible fix. I was on another forum talking to a "C5 Mechanic" and he said with the codes I have, change the "Ignition Lock Cylinder". This made sense to me as you could really move my key around when it was in the ignition. Lots of play. So I bought a new one, had it coded for my key at the local Chevy dealer and installed it. Extreme improvement over the old one as far as how tight the key fits. It doesnt budge now, no play what-so-ever. But, I turned it over and the SECURITY light came on as soon as I started it. So, I shut it down, re-installed the interior peices and went to start it again and it would not start. Gauges swept and got the electronics, but, it would not start. I had the following codes: P1631 H C and B2721 H. I waited about 10 or 15 minutes while I cooled down and went back out and it started with no SECURITY light. I grabbed my wallet and went for a ride. About 10 minutes into the ride the light came on again. I got home, shut it off waited a minute or so and started it back up. Started fine and no SECURITY light. The B2723 code came back as well. The next day I sprayed some WD-40 into the lock cylinder to lube it up a little as it was a little rough to turn the key. Made a good improvement. I installed the new lock cylinder on the 20th of Aug., since then the light came on that day and hasnt come on again until yesterday on my way home from work. I am lost as to what it could be. I have tried cleaning my key and that hasnt helped. The "C5 MECHANIC" told me that the thickness of the pellet on the key, from one side to the other, should be .177. I measured both my keys and they are .175 and .172, he said that is fine.

I am lost, I dont know what to do next. Should I spend the money and try a new key? I just hate the idea of throwing parts at it when I dont know for sure what is wrong. I dont mind putting in the new lock cylinder because the old one was in bad shape. I just cant believe that did not fix it.

Any help would be great!!!!!!

 

You only have the one key?

 

Have two keys, but it happens to both.

 

Spraying a non-conductive lubricant in the lock cylinder can only complicate things, and cleaning the key is negated by every insertion...so stop doing that. At this point, you will have to evaluate the Pass Key detection circuit from the BCM to the lock cylinder....using the schematics and a DMM.

 

Ok, wont spray anymore of that in there.

Schematics....ugh. I couldnt even begin to. Looks like I am taking it in. Unless someone can explain to me how to do it in a very easy manner!

 

http://forums.corvetteforum.com/c5-t...ch-repair.html

 

One question. Aside from your car key and lock/alarm key, how many other keys do you have on that ring?

I remember this from a really old thread: If you have a good amount of keys on the same ring, that could throw things off. I suggest that you segregate the cay keys from your other keys. Try that and report back.

EDIT: Even if it starts and you start driving, the bumps in the road and the weight of the keys together could be enough to throw the error too.

 

Knyght, I am down to the key and FOB on the ring. That was the first thing I did as, like you, I remembered that thread about to much crap on your key ring. I have done a good job about keeping things off it.

Doug, thanks for the thread link, but I dont think this has anything to do with the ignition switch. I will read through the thread again, just to see if there is any info about what I am experianceing, but I dont think this has to do with the ignition. Thanks though!!

 

The security pellet has to be read by the car, there is most likely a crusty contact inside the ignition switch not allowing your pellet(s) to be read correctly or at all.

 

I kinda have that feeling as well Doug. I am thinking about doing the DIY on it and see if it does anything. Hell, it has 70k on it now, so it couldnt hurt it even if it doent fix it. But sure wish I could pinpoint it.

 

The ignition switch and the key reader contacts are different items. BC has a good picture of the pellet reader.

 

Understand that they are different. Remember, I replaced the ignition lock cylinder, so the reader is new. I dont think it would be the new reader already messing up. I also dont think it is in the ignition switch, but like I said, I dont think it will hurt to go ahead and clean it up. Something else is wrong and I feel like Lucky is close, but again, I have no idea how to read schematics, let alone a multi-meter....

 

If you can't use a meter or read schematics, then you need a qualified mechanic or dealership...sorry.

 

Yea, thats what I am thinking as well. Gonna research online and see if I can find a site that explains how to read a schematic and see if I can fumble my way through it....

 

May have stumbled on something here. The past two days as I am driving to work, the light has come on. They are doing construction so the path of the road has changed a bit. There is a set of bumps I have to go over that throw the car around and I think the run flats make it that much more rough and bouncy. Yesterday and today as soon as I went over these bumps, the light came on. Not even a full two seconds after I went over them, the Security light came on. Could this be a clue? As I have mentioned, the new lock cylinder keeps the key tight! I dont think the key is moving.

 

Happened to me.....Almost same codes...

Sorry I think I was too eager to try and help.

After reading the post I think that maybe you'd already seen my post on the other forum. You did get one more code though.

I got a real scare, First attempt to start the car it didn't do anything. second attempt it fired up and hasn't failed since. Thank the Lord! If I am really in over my head and with electrical I usually am. I sometimes place my picture of Jesus on the dash at the start of the repair....

 

You know sometimes my 98 coupe will kick out some really scary codes and do some strange things. A lot of times it is a legitimate issue. But, strange codes will start after having worked on the car without disconnecting the battery. Maybe I bumped against a connector or something while working on a hose or something. So, sometimes before throwing too much time and energy into it I clear the codes. Disconnect the negative battery terminal in the evening. Leave it disconnected overnight. Reconnect and torque to spec the next morning. You have to have a good battery and lean it back to get a torque wrench on it. And the mystery code or problem goes away never to return. The car has 200000 miles on it. And has been great.

 

I have an '01Z that is doing the same exact thing. Save yourself the $54 and don't buy a new key. Been there and done that. I have removed the ignition switch two times and taken it apart for a good cleaning only to have the issue return after a couple dozen starts. Car is not a DD so it likely would rear it's ugly little head more if driven more.
Took a trip in it to SanFran bay area and it did it quite a bit. So pissed at it right now I have ignored it and not driven in since I got back. Picture it happening at a busy as hell gas station and the keys never left the ignition switch. Car starts up after the 3 minute time out as explained in the factory service manual. I sort of know why it is happening, I just don't know the where or how in the system.

Anyway, I have had the security light come on while driving over rough sections of road as well. One of those events was on the road to SF. Had been driving for over an hour on pretty smooth roads until I hit a real ugly spot and light came on instantly. Stays on until I stop the car.

All grounds have been apart, some of them several times (G102). No help.

Was adviced to install a new starter, did that before trip to SanFran. Didn't help.

Installed new battery 4 yrs ago, didn't help - battery now is on CTEK and is the same 4 yr old Optima red top. Issue has been with me that long.

The last time I had the interior out I took the ignition switch/lock out and measured the ohms with a DMM and the ohm's from the key are good (888 ohms). Key alone is 888 ohms, so no extra losses.

Car is never driven in the rain so floorboards are dry and BCM area is very clean and dry as well. I have taken BCM out a few times to look over the pins to make sure one didn't get bent or some other thing. Going to do that again and test each one of the female pins for a solid feel.

When the no start happens I can hear relays clicking from the passenger side of the car. I also hear the fuel pump prime every time like is should during the guage sweep calibration process.

At this point I feel it is a wiring issue within the harness and I have to find the culprit.

 

I've had issues with the passkey system on a Camero and a Caddy. Not much theft around here so I just hard wired in a resistor the same value as the key. Not reccommending it, but could be a troubleshooting tool.

 

Hey Kennya35, I broke out my service manuals and came across a paragraph that pretty much explains exactly what we are both describing in this situation. I'll quote it here from Vol3, Pg 8-723 under the VTD description and operation section:

If the PASS-Key system detects an open or short to ground when the ignition switch is in the RUN position, the BCM will default to fail enable mode. Fail enable occurs when the proper key resistance is sensed before the open short to ground occurs. Fail enable will illuminate the security indicator lamp and allow the operator to stop and start the vehicle until the problem is corrected. The PASS-Key system includes the following components:
Ignition key
Ignition cylinder
BCM
Theft Deterrent relay (TDR)
PCM
Security indicator

Correction: this is what is happening when the Security light comes on while driving down the road. Usually when I hit a hard bump.