03 Silverado passlock/igntion issues

[keithgreen69]

I have a 2003 Silverado that has starting issues. I first noticed this about 2 months after I changed the battery. The key fob does not work, so I mannually unlock the door, get in, and it cranks but doesn't start. I try to reprogram the fob but when I press the door unlock switch nothing happens. The security light does not come on nor does it flash. I've tried to turn the key to on and wait 10 minutes to reset everything and it still does not start. I turn the key off and on several times and try starting it. I do this for sometimes 2 minutes to 10 minutes straight and sometimes it will start. I always know when it will start because my headlights will suddenly come on after turning the key and it will start everytime that happens. OK, I thought it may be the passlock, so I dissassembled the dash and column covers. I found the connector that goes on top of the lock cylinder and with the truck running I dissconnected the plug. The security light came on and stays on(Normal I think..fail enable mode?) So I think I have the problem fixed....not. Once started, the key fobs work and there seems to be no issues. I shut it down and it will fire right back up everytime. Here is the problem, if I let it sit for longer than 5 or 10 minutes, it goes right back to the same problem. I am about half educated on this system but once the passlock plug is dissconnected, is there any other component that would be the cause. Lock cylinder contacts, bad key (I've tried all 3), ignition switch, or a possible intermittent BCM? I am really trying to figure this system out so I too can help others instead of the dealership charging an arm and a leg for parts and service. Please guys I need your help!! Feel free to reply here or email me at [email protected]. Thank you in advance.

[rockwood84]

the owners manual has the steps you use to re-program the system. this should get everthing back normal. if the battery is unhooked for a day or longer everything gets screwed up until it is re-programed.as for the passkey part it is not recognizing your key and it is doing what it was designed to do not crank and run without the correct key. re-program it and it will be normal..

[ukrkoz]

stand next to your vehicle; press and hold lock/unlock buttons simultaneously for 7 seconds. locks should cycle. that resets the fob/locks.

as of the passlock situation, call dealer and find the right protocol for passlock reset. i had it posted somwhere about 3 mths ago, but forgot which forum it was in.

ok, i got you covered, bud:

Here is the procedure.
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON, vehicle will not start.
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF. Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes, the vehicle is now ready to relearn the PasslockTM Sensor Data Code and/or passwords on the next transition from OFF to CRANK.
Important: The vehicle learns the PasslockTM Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
Start the engine, the vehicle has now learned the PasslockTM Sensor Data Code and/or password. With a scan , clear any DTCs if needed, DTCs will self clear after 100 ignition cycles


CREDIT DAVE NOVA. ALSO, I THINK, MODS COULD PUT IT A STICKY FOR THE FUTURE REFERNCE HERE. IT'S QUITE COMMON SITUATION.

[keithgreen69]

Thank you very much!! Ok I am actually at work right now but my buddy is at the house with the truck. Here is what he did. He has tried the above steps but no luck. The truck starts basically when it wants to. I disconnected the small black plug with the yellow, and red and white wire from the lock cylinder and the secuirty light stays on. I'm pretty sure that is normal. Earlier today I had the truck running, and I then disconnected the small black plug which I thought would dissable the passlock and it didn't seem to help. I tried hooking up a orange actron scanner to the truck but it would not recognize the tool. I just recieved a message saying that the tool needs to be connected to the vechicle. My buddy also tried the resistor trick by installing the resistors in the wires to fake the lock cylinder. Still no luck. Thanks for your replies. Please keep them coming. I really appriciate it!!

[ukrkoz]

ok, in such a predicament buy a passlock bypasser. i don't think i am using the right name for it, but there are plenty of those there that plug into the system and allow to bypass all that stupidity.

or try this:

(i see sticky again!!)

Yep. Turn the ignition to on. Your security or theft light should be flashing. This is "long tamper mode". Leave in the on position for 10 mins. and the light should turn on steady. You have reset the passlock system. If you are looking to "disconnect" your passlock, here is a modification that will work. There is no need to install the remote starter.

PASSLOCK I or II DISABLEMENT

The following is a procedure to disable Passlock I or II Systems for vehicles in which remote start/stop system installations are required. This procedure is required because a remote start system will not function with the current Theft Deterrent System (Passlock) which is included on many 1996 and up GM vehicles.

Please note that this modification is intended to be used only in conjunction with the installation of a remote start/stop system and does not provide a procedure to install a remote start/stop system.

CAUSE
If an attempt is made to start a vehicle by a means other than a key rotation in the ignition switch, the Body Control Module (BCM) will interpret this start as a vehicle theft and disable the fuel injectors.

CORRECTION
A minor wiring modification may be made to allow the vehicle to be started remotely. This modification includes adding a switch to allow the customer to select “ON” to disable Passlock or “OFF” for normal Passlock operation.

CAUTION: When this modification is performed and the switch is set to the ON position, the theft deterrent feature will be disabled. When the theft
deterrent is disabled the SECURITY or THEFT telltale will light up indicating that the theft deterrent system is NOT functioning.

PASSLOCK MODIFICATION
Refer to appropriate GM service manuals and/or SVMQP Electrical Guideline Manual for instruction on splicing and electrical connections.
1. Select a suitable on-off switch (see note below) which will be used to disable/
enable the Passlock System. Mount the switch in a location such that it is
accessible to the driver and will not interfere with normal vehicle operation.
NOTE: This is an extremely low current circuit (approx. 7mA), it is therefore very important that a high quality, low energy, fast acting switch be utilized
for this application.
2. Turn the ignition switch to the OFF position.
3. Locate the Main Ignition Switch Harness. GM's Passlock System wires exit the Ignition Switch Tumbler together and then join with the Main Ignition Switch Harness. (See http://www.bulldogsecurity.com/ or http://64.85.6.118/diagrams/diagrams.asp and select your Make, Model and Year for wire colors and clues on the quickest way to access these wires.)
4. Locate the Yellow Passlock Data Wire which is included in a bundle of three tiny (20 GA) wires wrapped in friction tape.
Cut this wire and splice a 0.5mm2 (20 GA) yellow wire to each end of the cut wire.
Keep wire length to a minimum. Route modification wires clear of moving parts.
Connect the yellow wires to the switch such that the contacts are OPEN when the switch is in the ON position.
5. Turn modification switch to the OFF postion (contacts closed).
6. Start vehicle to verify normal operation. If engine “cranks but will not start"
recheck the switch position (contacts should be closed), wire connectors and
modification wiring.

SWITCH OPERATION

To enable remote start:
Start the engine with the ignition key (modification switch must be in the OFF
position). Turn modification switch to the ON position (contacts open). The
SECURITY or THEFT telltale will light up indicating that the Passlock System is inoperative.
Once the SECURITY or THEFT telltale has been on for at least 5 seconds the vehicle can be turned off and then remotely started.

To disable remote start:
The Passlock System can be reactivated by turning the modification switch OFF
(contacts closed). Vehicle can either be running or off when this is done.

Please note that the VCM/PCM will record Diagnostic Trouble Codes (DTCs) related to the security system when the modification switch is in the ON position (circuit open). This is due to the way that the VCM/PCM interprets this condition.

NOTICE
Any condition which removes battery power from the Vehicle Control Module/Powertrain Control Module (VCM/PCM) (e.g. dead battery, disconnected harness connectors, etc.) will prevent the vehicle from being restarted. If the engine exhibits a “cranks but will not start” symptom, place the modification switch in the OFF (contacts closed) position. This will reactivate the Passlock System and allow the vehicle to be started with the ignition key.

Ray

[keithgreen69]

OK guys here is the latest. I bought a passlock bypass module and installed it. No luck. It seems to start only when it wants to. This is some things I've tried.

Put original key in crank it up..starts...unplug small plug on top of ignition lock cylinder..security light comes on and stays on...turn truck off...tried to restart with plug dissconnected....no start...security light stays on....plug small plug back in...crank it up...truck starts...security light goes out....let truck sit for 3 to 5 min....cranks but no start.

Also, when the truck was running, I tried to wiggle all wire harnesses to see if my security light would come on...nope. When the truck was cranking but not starting I turned the key on (Right before engine start) and wiggled all wire harnesses trying to see if "Driver 1" or headlights coming on would appear on the dash (That usually lets me know that it will start)...nothing.

I did the same above method with a cut key and the exact same results.

I removed the bypass module and hooked everything up in the original configuration.....same exact results.

each time I try different scenarios, I try to reprogram the BCM and still no luck. Am I doing anything out of sequence?
What else could cause a crank but no start?
When I install a bypass module, does it bypass the lock cylinder (Magnets for resistance), ignition switch, etc. In other words if a bypass module is installed what can I eliminate from the system? Thanks again guys for your help, once I learn this I am going to write a freaking book on the 2003 Silverado crank but no start problem and distribute it to everyone for free.

[briand069]

It seems to me you have pretty much beat the Passlock system to death and it is probably not the problem. It would probably make more sense to just start with normal trouble shooting procedures to determine why it doesn't start and at some point the security system will be included in the trouble shooting process.

[keithgreen69]

Yeah that is what I am trying to do right now. Fuses good, fuel filter changed, fuel pump working, etc. Something is shutting down the system like the passlock is supposed to. I am clueless!

[ukrkoz]

Originally Posted by keithgreen69

I have a 2003 Silverado that has starting issues. I first noticed this about 2 months after I changed the battery. .

you ever considred any other reasons than passlock? been awfully long time after you changed battery, it goes bad right on, not 2 mths down ther road. you might be preoccupied with wrong premise and keep hammering on the problem that is not there. scanned for codes?

[rockwood84]

keithgreen69, do you have the owners manual for the truck? if so in the manual it has a set of steps to re-program it. follow the steps exactly and if the switch is recognizing the key it will start.now if the switch is not sensing the correct key as the key has a chip in it and the switch might not be reading the chip.one other idea i have used before call a dealer and talk to a tech most will answer a few questions.i know a dude that lost his key and fob to a van and he ended up taking it to the dealer to get a new key and fob programmed for the van.get the battery load tested that way you can rule out the battery. did it do this before the battery was changed?

[keithgreen69]

No it did not do this before the battery was changed. I did the reprogram exactly by the book 3 times now. If I used the passlock bypass module won't it rule out the whole key theory. As of right now the bypass module is out and normal configuration is back to normal. One time I had the key on and tapped on the BCM and the dash lights came on and it started. We are checking all wires going in and out of the BCM. Junkyard wants $125 but chevy says I have to bring it to them to program. They also want $150 to diagnose problem for starters. I don't have a lot of money but I am running out of time.

[keithgreen69]

As far as codes go, I hooked a actron scanner up and it doesn't even recognize the truck. It just keeps telling me to hook the code reader to the vechicle.

[rockwood84]

if it started after you tapped on the bcm then you have a loose contact or wire going to bcm. not sure if the bcm has a ground wire or the bcm grounds to body. only ones i seen are black plastic and i have not held one to see how it grounds.the pass-lock is not the problem ,bcm area is where your problem is.g.m. does have alot of electrical problems due to too small wires and connectors to connections that are not moisture proof as supposed to be.do you have wiring diagram for the bcm?its not the starter

[rockwood84]

i just found somthing back in '04 a post about security system . the post was 2000 security system. page 211 check it out.

[keithgreen69]

Well after a long hard battle I finally had to submit. I have shot all the wires and found nothing. I called the dealership and asked them if they could run a diagnostic test and they did. They couldn't even get into the BCM to see what was going on inside. I should have it back in a few days. I really appriciate all of your help guys!! Thank you so much anf God bless!