See if this thread helps
http://forums.corvetteforum.com/show....php?t=1846342

If not, I would do advance search on topic of 'No Start' at both C5 Discussion and C5 Tech forums.

And when U resolve the issue be sure to update your thread with the fix so the next guy can benefit from your experience.

 

DID you ever resolve the security code issues. If NOT,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,, STICK A FORK IN IT,,,,,,,,, Its DONE.. That MUST be resolved before ANYTHING else is done. If it has, check the following

CHECK THE CONNECTIONS on the solenoid. Make sure that they are not loose.

If you want to throw parts at it, change out the Theft Deterrent Relay in the passengers foot well. Lok under the toe board above the BCM. You will see two relays. Change out the one with FOUR wires RED, PURPLE, Yellow and Yellow /Black stripe.

When it wont start, is the security light in the IPC, ON or OFF

Here is your schematic. Use the schematic and make sure that you have all the fuses checked.



Just cause tomorrow is FRIDAY, heres another valuable and handy schematic:

 

When it won't start the Security light comes off and then goes off like normal when you start it.


10-pcm p1631 h Thefy Deterrent Password Incorrect.
40-bcm b2721 h Pass Key Detection Circuit

Ok so it could be a issue with these two codes as you said correct? Any ideas? I replaced the key which didn't help? Could it be the ignition itself?

 

"When it won't start the Security light comes off and then goes off like normal when you start it."




TOO MANY "OFFs" If the security light is ON when you have the ignition ON,,,, its NOT going to START and its not going to RUN. If you have either DTC listed, ,, same thing


10-pcm p1631 h Thefy Deterrent Password Incorrect.
40-bcm b2721 h Pass Key Detection Circuit



The resistor pellet isnt making correct connection inside the sensor on the end of the ignition switch OR a wire or connection between the sensor and the BCM is bad.

BC

 

shaggy i am having the same issue with my 03 Z06. Ive replaced Theft Deterrent Relay, Battery, ignition tumbler, and the key. Still getting the p1631 and b2721 codes and no start. Exact same symptoms. I go out and try to start and it won't start....sit for a few and it might. Security light comes on after driving about 5 miles. Driving me crazy, I want to enjoy the car. Post up if you find a fix and I will do the same.

 

I applogize for that. I've not seen the security light stay on . When you first turn the car on when all the gagues come on you see it then it goes off. I have once or twice seen it come on after driving for a while.

I will clear all codes and see if those two come back, but I admit driving me crazy too.

 

Went out at lunch. Car would not start. Got some more info though.

Key in and turned on
Security Light blinking on and off. Check Engine light on. Radio on.

I went to diagnostic. Had one error other then the seat errors
40-bcm b2721 h

I cleared the error but it would not go to NO CODES it it stayed with the 1 BCM code.

I then tried to start the car. It fired but died right way. Did this 4 times. 5th time it started up.
Drove around town got gas, got food. Started fine each time.
Came back to work and looked at codes.
Still have 40-bcm b2721 h. This time though it let me clear the code and now shows NO CODES.

Shane

 

Went out after work and car would not start again.

Checked codes and there was only 1
10-pcm p1631

Cleared code and tried to start and it wouldn't Checked codes and only
10-pcm p1631

was back.

 

You havent changed or messed with the PCM or BCM have you??

Follow the procedure to match the passwords:

--------------------------------------------------------------------------------

DTC P1631 Theft Deterrent Start Enable Signal Not Correct
Circuit Description
This diagnostic tests for mismatched passwords between the BCM and PCM. Whenever replacing the BCM or PCM, follow the theft learn procedure in order for the system to learn the new password.

Conditions for Running the DTC
Mismatched passwords between the BCM and the PCM

Conditions for Setting the DTC
The PCM detects a wrong password from the BCM.
The fuel disable lockout is set.
The system has received an incorrect fuel continue password.
An invalid ignition key or malfunctioning ignition switch
The BCM was replaced.
Action Taken When the DTC Sets
The engine starts and then the engine stalls immediately.
The PCM stores the DTC information into the memory when the diagnostic runs and fails.
The Malfunction Indicator Lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time during which the diagnostic fails. The PCM stores this information in the Failure Records.
Conditions for Clearing the DTC
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
Use a scan tool in order to clear the DTC.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

The 11 minute and 30 second time criteria are a minimum required amount of time. The time limit can exceed this limit without interfering with the Auto Learn Procedure. Use a scan tool (VTD Auto Learn Timer equals Inactive) in order to determine when the 11 minutes has expired.

If DTC P1631 is set, this indicates that you did not follow the procedure correctly. Perform the Re-learn procedure again.

DTC P1631 Theft Deterrent System-Password incorrect Step
Action
Value(s)
Yes
No

1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important
Inspect for any BCM DTCs being set (except if you were sent here from PCM Replacement) before proceeding with this table. If a BCM DTC is set, refer to the appropriate BCM DTC.


Is a Tech 2 ® available?
--
Go to Step 4
Go to Step 3

3

Important:
This step is for United States and Canada vehicles only.
Maintain the battery voltage while the PCM is in the Auto Learn Procedure. Follow this procedure exactly as indicated or you will have to repeat the procedure from the beginning.
Performing the following procedure causes a DTC P1630 to set when you complete the procedure. This is the intended functionality. When P1630 sets, turn OFF the ignition for 30 seconds, then turn ON the ignition and P1630 clears. If the DTC P1630 does not clear, go to the DTC P1630 table.

Turn ON the ignition leaving the engine OFF for 11 minutes.
Turn OFF the ignition for 30 seconds.
Turn ON the ignition leaving the engine OFF for 11 minutes.
Turn OFF the ignition for 30 seconds.
Turn ON the ignition leaving the engine OFF for 11 minutes or until DTC P1630 sets.
Turn OFF the ignition for 30 seconds.
Turn ON the ignition leaving the engine OFF and wait 30 seconds.
Attempt to start the engine.
Does the engine start and operate normally?
--
Go to Step 5
Go to Step 6

4

Important
Performing the following procedure causes a DTC P1630 to set when you complete the procedure. This is the intended functionality. When P1630 sets, turn OFF the ignition for 30 seconds, then turn the ignition ON and P1630 clears. If the DTC P1630 does not clear, go to the DTC P1630 table.


Enter the Service Programming System (SPS) using a Tech 2.
Enter the vehicle information.
Choose the Request Info soft key on the scan tool.
Select Done.
Follow the instructions on the Vehicle Set-up screen.
Disconnect the scan tool from the vehicle.
Connect the scan tool to the Techline terminal.
At the Techline terminal select Service Programming System (SPS) and select terminal to Tech 2 programming method.
Select Done.
Follow the instructions on the remaining screens.
Select the Vehicle Theft Re-learn option.
Select Program at the summary screen. The terminal will download information to the Tech 2.
Return the scan tool to the vehicle.
Connect the scan tool to Diagnostic Link Connector (DLC).
Select Service Programming from the Tech 2 main menu.
Answer the prompts regarding the model year and vehicle type.
Press the Theft Re-learn soft key on the Tech 2.
Follow the instructions on the remaining screens.
The PCM and the BCM will be prepared for re-learn.
A security timer will be on for approximately 11 minutes or until DTC P1630 sets. It is important that during the 11 minute-wait, the user keeps the Scan Tool connected to the vehicle.
When the PCM and the BCM are prepared to re-learn, turn OFF the ignition for 30 seconds and then start the engine.
Does the engine start and operate normally?
--
Go to Step 5
Go to Step 6

5

Important:
Monitor all DTC status parameters and note any additional DTCs before Clearing DTCs.


Clear the PCM DTCs.
Turn OFF the ignition for 30 seconds.
Attempt to start the engine.
Does the engine start and operate normally?
--
System OK
Go to Step 6

6
Are DTCs P1626, P1630 or P1631 set?
--
Go to applicable DTC table
Go to Step 2



--------------------------------------------------------------------------------
Document ID# 317253
1999 Chevrolet/Geo Corvette

 

I have not done anything at all with the PCM or BCM.

This started about 2 years ago. I only drive the car in summer. 2 years it did it 3 times proabably. Last summer it started doing it a lot more probably once in 10 starts. Now it does it every start for the most part.

I'll try doing the learn this week or weekend.

Maybe that is it. Fingers crossed

 

Well,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,, That means that your BCM OR PCM is taking a dump.

If it were me,, and I was a BETTING MAN,,,,,, I would remove my BCM and remove the circuit board. When its out,, look for corrosion, damaged circuit traces, and anything out of the ordinary OR examine your PCM wiring and connectors and look for ACID DAMAGE.

Bill

 

that doesn't sound like fun.

Thanks I'll try the re-learn for kicks. I don't think the BCM has ever got wet. Its only been in the rain once since I've owned it for last 8 years. It leaks a little around window when I wash it, but its minor at best.

Just to be sure if it was the BCM pulling fuse 25 and putting it back in wouldn't prove it is bad or not right?


I'll do anything to get to drive the car daily. I just don't or can't loose my custome tune from LG.

 

Well.................... You use your AC,,,,,,,,,,,, Correct.. That means you CAN have moisture in your passengers foot well.

The HVAC condensate can overflow into the foot well.


If your HVAC Condensate Drain is clogged and you dont realize it,,,,,,,,,,,,,,,,,,, you have been driving in the rain for a LONG LONG TIME!



BC

 

I didn't think of that. I've used the AC probalby a dozen times in 8 years.

There was one trip 2 years ago I used it. Haven't since then.

 

Any luck yet. I've been following the thread and wondering if you have the problem resolved yet.

 

i am just a normal guy that bleeds GM blue. I have faith in my Chevys. Bill and 8vette7 KNOW what they are talking about listen to them! but keep it simple first....check the pos cable connection at the starter solenoid, then check the solenoid. just because you put a new starter and solenoid on, doesnt mean that it was a good one. i had the same issue with the no start sometimes. i was ready to start swapping parts. jacked the car up and pulled on the pos cable and could not move it at the solenoid. put a wrench on it any how. tightened maybe 1/16 of a turn. no problem starting in 3 months. i dont think that the cable was loose, but i do think that there was a loose conn inside the solenoid that i got lucky and tightened. cost $0.000

 

OK so I still have this issue that hasn't gone away. I'm thinking of replacing the BCM now. Where is the best place to get one?

I've pretty much exhausted most options now I think. I would like to sell the car and get a C6 now, but have to really get this fixed first.

 

I just went through a lot of this and ended up replacing the lock cylinder in the ignition switch....the wire lead was crimped causing all kinds of security glitches and' no starts' like you. Have you looked at your lock cylinder and ignition switch?

 

I have not. How do you get that off and checked?

 

there's a knee panel under your steering wheel that has to come off, after you remove your plastic console bezel where the radio and AC controller are mounted. Before you do any of that have a tech II analysis of the voltages at the switch....should be somewhere around 3 volts or so....I had spikes up to 5 volts when the wire on the lock cylinder was shorting out. It shorted out against a sharp metal edge under the dash...may have been that way since the car was built and finally rubbed through...no one knows for sure. Your dealer is now the only place that can sync up your keys to a new cylinder as GM no longer supplies a complete tumbler with springs and such.