Replaced ignition switch vehicle will not start appears to be computer code

Ignition what ? Switch ,Ignition lock cylinder ? New keys ? do they have the transponder pellet in the head. Do you have a security lit flashing when trying to start the vehicle ?
SECTION 419-01: Anti-Theft - PATS 1999 Mustang Workshop Manual GENERAL PROCEDURES Procedure revision date: 11/06/1998 Key Programming -Erase All Key Codes and Program Two Keys
Special Tool(s) > New Generation STAR (NGS) Tester or equivalent
418-F048 (007-00500) NOTE: This procedure is used when a customer needs keys programmed into the system and does not have two programmed ignition keys available. This procedure is also useful when programmed ignition key(s) have been lost or the ignition switch assembly has been replaced, and it is desired to erase key(s) from the passive anti-theft system (PATS) memory.
NOTE: This procedure will erase all programmed ignition keys from the vehicle memory and the vehicle will not start until two keys have been reprogrammed to the vehicle.
NOTE: Two PATS encoded keys with the correct mechanical cut must be available to perform this procedure. One or both of them may be the customer's original keys.
NOTE: If additional keys are to be programmed, refer to Key Programming - Program a Key Using Two Programmed Keys. If the remaining keys are with the customer and are not available with the vehicle, then instruct the customer to refer to the Owners Guide under the "Programming Spare [SecuriLock ® (North America), Safeguard ® (U.K.) or PATS for all other markets] Keys Procedure" for instructions on programming the remaining keys.

1. Turn the ignition switch from OFF to RUN.

1. Enter New Generation STAR/Service Bay Diagnostic System (NGS/SBDS). Follow the SECURITY ACCESS PROCEDURE to obtain security access.

1. From NGS/SBDS menu, select IGNITION KEY CODE ERASE.

1. NOTE: Do NOT select any additional commands from this menu.
   Turn the ignition switch to OFF and disconnect NGS.

1. Insert the first encoded key into the ignition lock cylinder and turn the switch to RUN for three seconds.

1. Insert the second encoded key into the ignition lock cylinder and turn the switch to RUN for three seconds.

1. The vehicle should now start with both ignition keys.

You'll need to take to the dealer

ur still in a security lock out with ignition[ key ] system u might have to have it towed to dealer for them to hook up vehicle[contact dealer and advise what is happening and also recheck new key] for reprograming or reset system..some vehicles if u try to start vehicle while in a security mode can get completely locked out of vehicle and if u replaced the whole ignition housing and not just the cylinder the housing is the reader the wiring that is around the housing cylinder tube is what reads the key and syncs with the vehicle if u put in a different one or the wiring is damaged vehicle wont start and will stay in security mode

All you have to do to reset the antitheft system is to lock the doors with the key fob.

Your new key has to be programmed to your engine computer (PCM) before it will work.

To program, follow the directions in your owner manual. You need 2 already rpogrammed keys to do this.

If you don't have 2 programmed keys, your dealer will have to use his diagnositc tool to retrieve the information from the computer. Always have 2 programmed keys. I actually keep 3 in case I lose one, I still have 2 to program a 3rd one myself.

If you have AAA, have it towed to the delaer as a "no Start" so you don't have to pay the tow charge.

I assume this new ket is your only key now, or you could drive to the dealer with your spare key.
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SECTION 419-01B: Anti-Theft - Passive 1999 Cougar Workshop Manual GENERAL PROCEDURES Procedure revision date: 09/14/2001
Key Programming Using Two Programmed Keys NOTE: This procedure only works if two or more programmed ignition keys are available and it is desired to program additional key(s). If two keys are not available. For additional information, refer to Key Programming - Erase All Keys and Program Two Keys in this section.
NOTE: PID SPARE - KY must be enabled for this procedure to operate. If this PID is not enabled, refer to Security Access then select Spare Key Programming Switch; Enabled.
NOTE: If the programming procedure is successful, the new key(s) will start the vehicle and the anti-theft indicator will illuminate for approximately three seconds.
NOTE: If the programming procedure is not successful, the new key(s) will not start the vehicle and the anti-theft indicator will flash. If the programming procedure was not successful leave the ignition switch in the RUN position for at least 30 seconds, repeat the Key Programming procedure from Step 1. If the failure repeats, refer to Diagnostic and Testing to review DTCs an carry out Pinpoint Tests.
NOTE: A maximum of eight ignition keys can be programmed to a passive anti-theft system (PATS) equipped vehicle.
NOTE: If the steps are not carried out as outlined, the programming procedure will end.
NOTE: Ignition keys must have correct mechanical key cut for the vehicle and must be a PATS encoded key.

1. Insert first programmed key into ignition lock cylinder and turn the ignition switch from the OFF position to the RUN position (maintain ignition switch in the RUN position for one second).

1. Turn ignition switch to the OFF position and remove the first key from the ignition lock cylinder.

1. Within five seconds of turning the ignition switch to the OFF position, insert the second programmed ignition key into the ignition lock cylinder and turn the ignition switch from the OFF position to the RUN position (maintain the ignition switch in the RUN position for one second).

1. Turn the ignition switch to the OFF position and remove the second key from the ignition lock cylinder.

1. Within ten seconds of turning the ignition switch to the OFF position , insert the unprogrammed ignition key (new key) into the ignition lock cylinder and turn the ignition switch from the OFF position to the RUN position (maintain the ignition switch in the RUN position for one second).

1. If it desired to program additional key(s), repeat the applicable key programming procedure from step 1.
2. ----------------------------------------------------------------------------------------------------------------------------------

Passive Anti - Theft System (PATS)
The Passive Anti-Theft System (PATS) is fully passive in operation and requires no special procedures by the driver to arm or disarm the system. It is invisible to normal scrutiny and is operated by a miniature transponder within the key body. The transponder communicates with the powertrain control module through a transceiver mounted around the ignition switch lock barrel. The PATS functionality is incorporated within the powertrain control module.
PATS may be identified by a larger than normal sized ignition key. A larger sized ignition key indicates the presence of the transponder that controls the system.
The transponder code reading is carried out when the key, having been inserted into the ignition lock barrel, is turned from position ``0'' to position ``II'' to crank the engine. If the PCM receives the correct code, the engine will start. If the PCM receives either no code or an incorrect code the engine will not crank and PATS remains armed and the engine immobilised.
Anti-Theft Indicator
Whenever the ignition is switched on the anti - theft indicator will remain on for three seconds while the system reads the ignition key code.
The anti - theft indicator will flash rapidly or glow continuously after the initial three seconds to indicate the PATS has immobilised the vehicle.
For additional information on the PATS fault codes, refer to the Diagnosis and Testing section
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The PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code out of over four quadrillion combinations.
Each encoded ignition key must be programmed into the vehicle's powertrain control module (PCM) before it can be used to start the engine. There are special diagnostic repair procedures outlined in this manual that must be performed if an encoded ignition key needs to be replaced
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Make sure you have the right type of ignition keys, there should be a stamp on the keys "PK3" which is the right ignition keys you need to have for your passlock system.

Auto Relearn:
Time required, approximately 10 minutes.

Insure that the battery is fully charged.
Turn the ignition switch from the OFF position to the CRANK position attempting to start the vehicle. The vehicle will start and then stall.
Leave the ignition switch in the ON position while observing the security indicator.
When the security indicator turns off, which can take up to 10 minutes, turn the ignition switch off. Wait 10 seconds.
The BCM and the PCM will learn the new code on the next start attempt.

You may have to get somebody with a scan tool to reset the computer codes to make this work.

Thank oyu for using fixya and good luck

Yes you can install and new ignition switch in your Blazer, once you have installed the new switch, your going to have to do a PASSLOCK II relearn for the new ignition key's to start the Blazer.
PASSLOCK - Reprogramming Auto Learn

IMPORTANT:

* The Body Control Module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See BCM Programming/RPO Configuration.
* If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn PASSLOCK sensor data code immediately. The existing VCM/PCM however, must learn the new fuel continue password when the BCM is replaced.
* If replacing a VCM/PCM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password immediately upon receipt of a password message. Once a password message is received, and a password is learned, a learn procedure must be performed to change this password again. A VCM/PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password and will require a learn procedure after programming to learn the current vehicle's password.

CONDITIONS
Use this procedure after replacing:

* Passlock Sensor
* BCM
* VCM
* PCM

30 MINUTE RE-LEARN PROCEDURE

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds .
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the PASSLOCK Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK). IMPORTANT: The vehicle learns the PASSLOCK 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.
6. Start the engine (the vehicle has now learned the PASSLOCK Sensor Data Code and/or password).
7. With a scan tool, clear any DTCs if desired (history DTCs will self clear after 100 ignition cycles).
Thank you foe using Fixya

Ok then, from your description and the
make/model/year of the car you have there,
it appears you've reset the VATS.

The car's security immobilizer
reader at the key switch
does not recognize the coded
chip in the ignition key any longer.

You can try to put the key
in the ignition, turn to the on position &
wait at least 10 min like that.
(Do not turn off the key switch before
10 minutes as elapsed!)

Once done, the key is re-programmed and
should allow the fuel injectors to work again.
The car would start now if corrected.

In some cases, the VATS (GM'S VEHICLE ANTI THEFT SYSTEM)
will re learn the code this way, and will then
allow the restart, however if this does not work,
then you can simply tow it to any GM vehicle dealer
to have the service department re code it.

There is a permanent solution though.
Adding the PLJX Self learning Bypass module (59.95)
will bypass the PASSLOCK system in your vehicle
for good. See this at www.PASSLOCK2.com

Good luck I hope method 1 does the trick!

Here is the 30 min relearn:

Ignition keys relearn takes about 30 min to do. 30-Minute Learn Procedure 1. Turn ON the ignition, with the engine OFF. 2. Attempt to start the engine, then release the key to ON; the vehicle will not start. 3. Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF. 4. Turn OFF the ignition switch, and wait 5 seconds. 5. Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes. The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK Important: Turn the Ignition Switch OFF. The vehicle learns the Passlock 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. 6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password. 7. With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles. Without a scan tool you may have momentary starter interruptions while history clears itself.

groan.....gunna need a bit more info. but i'll try. What portion of the ignition was ripped out? The tumbler + switch? If so, you might need to get the car's system resent to recognize that it has a new ignition put in. Sime vehicles have a theft prevention system in place to prevent the vehicle from running if its been hot wired. Your best bet would be to replace the damaged ignition components (You did not mention if you did or not). If it still doesn't work after you have replced all of the ignition components. You can try to reset the vehicle (doesn't work on all) disconnect negative battery terminal and go back into vehicle and press down the brake pedal for about 30 seconds then reconnect battery and try it....good luck, hope this helps

Your key has a computer chip in it that tells the computer that the person who owns the car is trying to start it. Sometimes the key will lose its memory and the car computer thinks your a thief with the wrong key. You may have to have a new key made from a code the dealer can aquire from the VIN number I believe.

the anti-theft light is supposed to blink when the car is locked to show the system is armed.

Does it flash while driving?

Principles of Operation
The PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code out of over 18 billion, billion combinations.
The passive anti-theft system (PATS), also known as SecuriLock ®, uses radio frequency identification technology to deter a driveaway theft. This system is known as Securilock® in North America, Safeguard® in the U.K., and PATS in Continental Europe. Passive means that it does not require any activity from the user.
The SecuriLock® System (PATS) is not compatible with aftermarket remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. If equipped the remote start system must be removed before investigation of PATS-related, no-start issues.
Each encoded ignition key must be programmed into the vehicle's powertrain electronic control (PCM) before it can be used to start the engine. There are special diagnostic repair procedures described in this section that must be carried out if a new encoded ignition key is necessary.
This system contains a new feature named Unlimited Key Mode. This feature allows a customer to program more than eight keys to the vehicle if they request it. Each vehicle in Unlimited Key Mode is set up with a special Unlimited Transponder Security Key. This allows all the customer vehicles to share the same keys, but no other keys from outside can be used to operate the vehicles. For an individual customer, any randomly selected Security Key is acceptable. Refer to Unlimited Key Mode Programming in Key Programming Switch State Control in this section.
The PATS transceiver module communicates with the encoded ignition key. The module is located behind the steering column shroud and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends data to the PCM.
The control functions are contained in the PCM. This module carries out all of the PATS functions, such as receiving the identification code from the encoded ignition key and controlling the engine enable. The PCM initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.
All elements of the PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.
The PATS uses a visual theft indicator. The indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS concern, this indicator will either flash rapidly or glow steadily when the ignition switch is turned to RUN or START. The PATS system also flashes the theft indicator every two seconds at ignition OFF to act as a visual deterrent.
The following will activate the PATS and will disable the vehicle from starting:

• incorrectly encoded ignition key
• damaged encoded ignition key
• unprogrammed key
• non-encoded key (key has no electronics)
• damaged wiring
• damaged transceiver
• damaged PCM

what year?

here's 1990. It may be the instrument cluster that's the issue.
You never said what the prnlem is.
Did you reporgram the keys to the new module?

Please rate as fixe
Anti-Theft —PATS The passive anti-theft system (PATS) contains the following components:

• theft indicator
• encoded ignition key
• transceiver module
• instrument cluster
• powertrain control module (PCM)
• standard corporate protocol (SCP) communication network

The PATS uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user. This system is known as SecuriLock® in North America, Safeguard® in the U.K. and PATS in continental Europe. This information can be found in owners literature.
The PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code, with over 72 million billion combinations.
Each encoded ignition key must be programmed into the vehicle's instrument cluster (the instrument cluster is also known as a hybrid electronic cluster [HEC]), before it can be used to start the engine. There are special diagnostic procedures outlined in the workshop manual that must be carried out if new encoded ignition keys are to be installed.
The encoded key is larger than a traditional ignition key. The key does not require batteries and should last the life of the vehicle.
The transceiver module communicates with the encoded ignition key. This module is located behind the steering column shroud and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends the data to the instrument cluster.
The control functions are contained in the instrument cluster. This module carries out all of the PATS functions such as receiving the identification code from the encoded ignition key and controlling engine enable. The instrument cluster initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.
The PATS uses the PCM to enable or disable the engine. The instrument cluster communicates with the PCM over the SCP network in order to enable engine operation. The instrument cluster and the PCM use sophisticated messages in order to prevent a theft. The instrument cluster and the PCM share security data (when first installed together) that makes them a matched pair. After this security data sharing, these modules will not function in other vehicles. The shared PCM ID is remembered even if the battery is disconnected. The instrument cluster also stores the vehicle's key identification code even if the battery is disconnected. There are special diagnostic procedures outlined in this workshop manual that may be carried out if either a new instrument cluster or PCM needs to be installed.
All elements of PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.
PATS uses a visual theft indicator. This indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS problem, this indicator will either flash rapidly or glow steadily (for more than three seconds) when the ignition switch is turned to RUN or START. PATS also "blips" the theft indicator every two seconds at ignition OFF to act as a visual theft deterrent.
The PATS is not compatible with aftermarket remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. Remote start systems must be removed before investigation of PATS-related no-start issues.
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Symptom Chart Condition Possible Sources Action

• No communication with the module — instrument cluster

• Central junction box:
  • Fuse 2 (5A).
  • Fuse 6 (5A).
  • Fuse 30 (30A).
• Circuitry.

• GO to Pinpoint Test A .

• The anti-theft indicator is always/never on — no three-second theft indicator prove-out

• Instrument cluster.
• Theft indicator.

• GO to Pinpoint Test B .

• The vehicle does not start — theft indicator proves out for three seconds as normal

• Less than two keys programmed to the system.
• Transceiver not connected/defective.
• Circuitry.
• Transceiver internal antenna damaged.
• NON-PATS key, damaged key or no code received.
• Partial key read of PATS key.
• Unprogrammed PATS key.

• PERFORM instrument cluster on-demand self-test. RETRIEVE DTCs. If DTCs are present, GO to Instrument Cluster Diagnostics Trouble Code (DTC) Index. If no DTCs are retrieved, CHECK for other possible no-start causes.

• No PCM ID stored in PATS.
• PATS/PCM ID do not match.
• Problem with SCP link.

• CLEAR the stored DTCs. CYCLE the ignition key from off to run. RETRIEVE continuous DTCs. If DTCs are present, GO to Instrument Cluster Diagnostics Trouble Code (DTC) Index. If no DTCs are retrieved, CHECK for other possible causes.

• The alarm system does not operate properly — the vehicle starts but flashes a fault code on theft indicator at key on

• Incorrect PCM calibration.

• GO to Pinpoint Test C .

--- Key Programming —Program a Key Using Two Programmed Keys NOTE: This procedure only works if two or more programmed ignition keys are available and it is desired to program additional key(s). If two keys are not available, follow the procedure in Key Programming—Erase All Key Codes and Program Two Keys .
NOTE: PID SPARE_KY must be enabled for this procedure to operate. If this Parameter Identification (PID) Index is not enabled, follow the security access procedure and select Spare Key Programming Switch: Enabled.
NOTE: If the programming procedure is successful, the new key(s) will start the vehicle and the THEFT INDICATOR will illuminate for approximately three seconds.
NOTE: If the programming procedure is not successful, the new key(s) will not start the vehicle and the THEFT INDICATOR will flash. If the programming procedure was not successful, repeat the key programming procedure from Step 1. If the failure repeats, check Circuit 729 (RD/WH) (hot at all times) in instrument cluster for proper battery voltage. Repair the circuit if voltage is not present. For additional information, refer to Diagnosis and Testing to review diagnostic trouble codes (DTCs) and perform pinpoint tests as required.
NOTE: A maximum of eight ignition keys can be programmed to a passive anti-theft system (PATS) equipped vehicle. Use PID NUMKEYS to determine how many keys are programmed to the vehicle.
NOTE: If the steps are not performed as outlined, the programming procedure will end.
NOTE: Ignition keys must have correct mechanical key cut for the vehicle and must be a PATS encoded key.

1. Insert the first programmed ignition key into the ignition lock cylinder and turn the ignition switch from OFF to RUN (maintain the ignition switch in RUN for one second).

1. Turn the ignition switch to OFF and remove the first key from the ignition lock cylinder.

1. Within five seconds of turning the ignition switch to OFF, insert the second programmed ignition key into the ignition lock cylinder and turn the ignition switch from OFF to RUN (maintain the ignition switch in RUN for one second).

1. Turn the ignition switch to OFF and remove the second key from the ignition lock cylinder.

1. Within 10 seconds of turning the ignition lock cylinder to OFF, insert the unprogrammed ignition key (new key) into the ignition lock cylinder and turn the ignition switch from OFF to RUN (maintain the ignition switch in RUN for 1 seconds