Every once in a while I will try to start my car and the gauges will sweep and the fuel pump will prime and then nothing at all happens...

I have already cleaned my key, removed the keychain from the key, cleaned the ignition cylinder as well as I can and bought a brand new key and the problem still happens

I am out of warranty and I dont want to go to the dealer with no ideas of what the problem is. Another member was having a problem and his dealer said all they needed to do was reflash the BCM... I had my doubts about that and it turned out to do nothing.

I am thinking that changing the ignition cylinder is the next course of action... how much $$$$$ is reasonable for the dealer to do this?

 

I just replaced my starter at 90,000 miles, was having the same problems. How old is your battery?

 

I had a similar problem with my 2003 Trailblazer. The gauges would sweep but nothing would happen when I turned the key. The problem occurred very rarely at first (twice in 6 months) then started happening very frequently. I took it to the dealer and it turned out to be a bad ignition switch which they fixed under warranty. The tech had it diagnosed and fixed in an hour.

 

pull the codes and post them here.

 

P1631 is the only code that is popping up.

 

I am not sure as I bought the car used... but it looks new and the voltage is good and the connections are very clean. I am leaning towards just biting the bullett and getting the ignition cylinder replaced.

 

Funny, I'm starting to have a similar problem. Started last week. I used my 2nd key when it happened, and vavoom, that one worked. Left the car home and when I came back, tried the first key again and it worked this time?!?!?!

I didn't touch a thing except for checking the resistance of the chip in the keys (which matched, showing one hadn't failed). That's right, no contact cleaner, no emory paper....nothing different but the first key started working again.

A forum member posted that the chassis grounds deteriorate/corrode and can cause all sorts of weird electrical problems. Once I get moved into my new house, I'm going to clean and protect my grounds and keep my fingers crossed. Search my name for my 1st key nothing, 2nd key works post and you'll find his post linked in there....he's got great pictures and schematics to show exactly where to locate the grounds and what to clean. Good luck!!!



- TC

 

We had this problem on our O4 vert as well. Finally it died and we had it towed to the dealer. It took them 2 days to figure it out.
It was a loose wire on the fuel pump.

 

P1631 is "theft deterrent password incorrect", I see a pattern developing here on the forum.
While many things in the system can cause this code, I chased it until I found the root cause.
In my case it was the ignition lock cylinder, and I will bet there will be a lot of them out there.
There are 2 tiny wires that are flexed every time you turn on the ignition switch because they are attached to the lock cylinder where the contacts touch the resistor pellet.
To make matters worse it is an intermittent thing and when it happens you have to wait for the TDS to time out (3-4) min. before trying again or it starts the cycle over again.
I actully had to remove the lock cylinder and clamp it in a vise carefully and attach a digital ohm meter to the wires so it could be tested.
I found every so often it would show a different resistance for a second, just enough for the BCM to activate the TDS.
The way the elimate the starter from the equation is to jump the terminals on the solonid when there's a failure.
If it engages then the issue is inside the passenger compartment.
Oh and don't let anyone tell you they reflashed the BCM it can't be done, you can only do a key relearn to accept a new ignition key.
Good luck and keep us posted.
Bob

 

I wasnt the one that had a dealer reflash the BCM... I am by no means an expert, but I didnt think that was possible either. I have a message into Fichtner Chevy about parts for replacing the cylinder... is it something a shade tree mecahnic could do?
I have read about the relearn process... the turn key for 11 minutes, turn key off for 30 seconds etc...

is this something I shoud just turn over to the dealer?

thanks a lot

 

Only you can answer that question, really it's not rocket science it just requires a service manual and patiance.
You will have to code the new lock cylinder to your key since they come uncoded.
Just disassemble the old lock and remove the key section from the block and you will find a rectangle sheet metal piece. Remove that carefully and remove the little springs and wrap the cyl with clear scotch tape and turn it upside down and tap it until all the little brass tumblers are stuck to the tape. then carefully with a pair of tweezers remove 1 at a time and place them in the new cyl. in the same position and order they came out of the old one. Reinstall the springs and the sheet metal cover on the new cyl. and assemble with the new block, check for function and assemble to the switch and reinstall in the car.
You can IM me if you have any questions.
Bob

 

I had the same problem. My ignition cylinder was replaced for about $300 at the dealer and the problem hasn't happened since. Of course the dealer broke the bezel off the ignition switch, but that is a different story.

Once the cylinder reads the wrong code, it will disable the ignition for five minutes. and flash the security light on the dash.

 

I have an '02 vette and had it happen to me, for the first time, last week. I thought it was a fluke, but now you guys have me worried. Maybe chevy will do a recall and replace the bad component (Ha!)

 

thanks for chiming in that makes me feel a little better. My dealer said about $260 out the door. Of course the part is $107 and I can get it from gmpartsdirect for $42.52
sounds like my local Chevy dealer must mark up parts about 300%... so that must be the dreaded Corvette tax

 

Man, I searched for this last week and couldn't find anything on it, but the servers are causing problems. corvettebob1, thanks for sharing the info. Looks like this is exactly what is happening to me.

Anyone come up with a work-around yet to bypass the cylinder lock when it finally wears out? Seems like you could wire in a resistor that matches the key and permanently work around the issue.....but maybe the BCM is too smart for that???? Talk about high maintenance? All this (column lock issue and now ignition issue) just so some stupid thief won't steal my car!

 

I could be crazy, but I would swear that I remember someone coming up with a VATS bypass for the C4... of course I have been wrong before.

 

Sure you could wire in a resistor of the same value of your key pellet but do you really want to do that?
I believe there are 15 different pellets with some varration in each ones resistence.
I know I measured both of my keys and they are slightly different, not sure if it's because I only use one 99% of the time but they are slightly different.
Without this protection they could just ****** out the cylinder and start your car with a screwdriver and drive it away.

 

I know, I know....I was just ranting. I'll fix it the right way since the part is only @ $50. I'm beginning to think I need to join AAA, though.

I used an analog ohmmeter and it appeared that the resistance in my primary key a little low, but then after repeatedly testing each of the keys, and adjusting the meter, they began to read the same. I wonder how often the resistor in the key goes bad and if time or frequency of use is the bigger factor? Just thinking out loud. Maybe an electronics guru will chime in.

Say, what part of the wire connection to the cylinder failed? Any idea, or was it an invisible gremlin somewhere in the mechanism causing the resistance change?

 

funny you would say that.... I just joined a motorclub tuesday

if you are serious, check www.gmmotorclub.com

 

Alright, this is rediculous... I had the coloum lock issue and GM didn't want to cover me so I had to pay out of pocket. Now I too got the ignition problem (only once so far) but I'm sure I'll be getting it again. I've had my car for 4 months now and I've soaked around a thousand into it. I love it to death but I don't think I'll buy another one with GM's horrible customer care.

I have no problem paying for items that break on their own, but I can't stand issues that are out of my control like this and the coloumn lock

Sorry, just ranting cause I was hoping this problem wasn't a problem and just a fluke..