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Celia Webster
Celia Webster Posted on Mar 08, 2019
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2005 chevy impala new PCM, BCM and ignition switch. Code P1631 Security. Any ideas as to what could be causing the security issue?

2005 chevy impala new PCM, BCM and ignition switch. Code P1631 Security. Have had everything programmed, and have done a relearn on it. Will not even attempt to turn over, no crank at all. Power to everything except the radio. Have checked fuses and even put in a new Starter relay switch. Any ideas as to what could be causing the security issue?

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Jeff Armer

Jeff Armer

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  • Chevrolet Master 3,418 Answers
  • Posted on Mar 08, 2019
Jeff Armer
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DTC P1631 Theft Deterrent Fuel Enable Signal Not Correct

The powertrain control module (PCM) controls the fuel injector operation and the starter operation based on a vehicle theft deterrent (VTD) password from the vehicle body control module (BCM). When the ignition is first turned ON, the BCM sends a programmed theft deterrent password to the PCM. The PCM acknowledges the password and responds to the BCM that normal fuel injector and starter operation will continue. If the PCM detects an incorrect password, a theft deterrent system failure, or an attempted vehicle theft, DTC 1631 will set. The engine will not start or crank as long as the condition is present.

Diagnostic Aids
DTC P1631 indicates that the vehicle theft deterrent password that the PCM has learned does not agree with the password received from the VTD system. This condition can occur if the BCM has been replaced and the PCM Password Learn function has not been enabled. If the BCM has been replaced, the password must be relearned.


Step
Action
Yes
No
1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Perform the Password Learn Procedure. Refer to Programming Theft Deterrent System Components .
Did you complete the procedure?
System OK

30-Minute Learn Procedure
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON; the 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 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.
Start the engine. The vehicle has now learned the Passlock™ Sensor Data Code and/or password.
With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles.

  • 2 more comments 
  • Celia Webster
    Celia Webster Mar 09, 2019

    Update... Have done the 30 min relearn and still no crank. Replaced the starter relay with no change. Suddenly no power to the radio either. The fuel pump relay is clicking rapidly and when changed out there is no change. Any other help as to why my car won't start? I have run out of funds to put into it. Had a gentleman come out 2 times to flash 2 different BCM's due to the first one being "locked" bought a new one and had it done at quite a cost. He programmed and did the relearn procedure, nothing. He reset the security but still having a security issue. No crank and still pulling code P1631 Security. Help!!!!!!!

  • Jeff Armer
    Jeff Armer Mar 09, 2019

    Replacing relay's isn't going to fix it . Hooking up a factory or professional scan tool an looking at data parameters in the BCM sent to PCM to see where the signal is getting lost. You probably have no idea what i'am taking about .
    The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent system prevents the vehicle operation if the correct key is not used in order to start the vehicle. The ignition key turns the ignition lock cylinder. The cylinder rotation produces an analog voltage code in the Passlock™ sensor. This voltage code is received by the BCM. The BCM compares the voltage code to the previously learned voltage code. If the codes match, a class 2 message is sent from the BCM to the powertrain control module (PCM). The message enables the fuel injectors and the crank relay.

  • Celia Webster
    Celia Webster Mar 10, 2019

    Okay, that doesn't help me though. We had a professional do the scan and program. He is the one that told me of the security code. Was not able to figure it out any farther than that however. He checked the security issues and could not bypass anything. Said the PCM and BCM were fine, communicating with each other, but couldn't get past the security part of it.

  • Jeff Armer
    Jeff Armer Mar 10, 2019

    Well ,you better find another (better) professional because your not going find the problem on here , it's going to take a trained tech that knows how these systems work , without hooking up a tech 2 scan tool an viewing data for anti-theft no one is going to be able to say for sure without testing .

×

5 Related Answers

A

Anonymous

  • Posted on Aug 11, 2008

SOURCE: 2003 Caravan No Crank, 3.3L

This is a bad PCM. Try to disconnect the security system first and if it still does not start then it is the PCM.

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Anonymous

  • 1 Answer
  • Posted on Apr 15, 2009

SOURCE: MY 2002 CHEVY IMPALA 3.4 DRIVE FOR A WHILE THEN SHUTS OFF

Sounds like an altinator problem. Have it checked out. If your altinator is bad it will not recharge your battery while its running and cause your car to lose all electrical power. When this happens, your car will not usually run for more than 10minutes or so.

Anonymous

  • 79 Answers
  • Posted on Sep 13, 2009

SOURCE: 1998 chevy truck security light then fuel pump

Check the pressure regulator. Refer to the manual on this site for location and proper pressure.

Anonymous

  • 15935 Answers
  • Posted on Sep 24, 2009

SOURCE: engine will not turnover

If there is no power coming IN to the starter relay - the ignition module has failed.
Replace the Ignition.

Thanks for using FixYa - a 4 THUMBS rating is appreciated for answering your FREE question.

Anonymous

  • 10 Answers
  • Posted on Jan 28, 2010

SOURCE: 2003 impala -starter will not engage/no interior

youre problem posible cuase by ignition swith possible no supply from battery.maybe wire were disconnected

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Related Questions:

0helpful
1answer

Olds Alero Security
IS their a certain part on ignition switch that could be faulty ????? Rather then looking to replace parts that may not fix the problem ,take an have a scan tool hooked up an have code's in the BCM - body control module .Qualified repair shop. The BCM controls the anti-theft . Not to auto zone or pep boy's or advance etc. They can not read BCM code's .
Passlock?"¢ System
The Passlock?"¢ System is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate or the ignition switch is operated while separated from the ignition lock cylinder case. If starting is attempted without authorization from the Passlock?"¢ System, the powertrain control module (PCM) will disable engine starting. Start disable may be in the form of fuel disable or starter disable, depending on engine application.
The components of the Passlock?"¢ System are as follows:
?€¢
The ignition lock cylinder and key


?€¢
The ignition lock cylinder case, including the Passlock?"¢ sensor


?€¢
The ignition switch


?€¢
The body control module (BCM)


?€¢
The security indicator on the instrument cluster


?€¢
The powertrain control module (PCM)


Do you know what DTC'S - diagnostic trouble code's are
DTC B2947 DTC B2948 DTC B2957 DTC B2958 DTC B2960 DTC B3031 DTC B3033 DTC P1626 DTC P1630 DTC P1631 DTC P1632

Read full answer
Nov 29, 2018 • Cars & Trucks
0helpful
1answer

2005 chevy classic new lock and keys starts and runs if off more then 10 minutes antitheft comes on and have to wait 10 minutes starts again any idea?
Yeah , take it to a qualified repair shop. You have a anti-theft system problem . Need to have code's pulled
DTC B2947
DTC B2948
DTC B2957
DTC B2958
DTC B2960
DTC B3031
DTC B3033
DTC P1626
DTC P1630
DTC P1631
DTC P1632

This will point to a diagnostic procedure .
The Passlock™ System is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate or the ignition switch is operated while separated from the ignition lock cylinder case. If starting is attempted without authorization from the Passlock™ System, the powertrain control module (PCM) will disable engine starting. Start disable may be in the form of fuel disable or starter disable, depending on engine application.
The components of the Passlock™ System are as follows:
• The ignition lock cylinder and key
• The ignition lock cylinder case, including the Passlock™ sensor
• The ignition switch
• The body control module (BCM)
• The security indicator on the instrument cluster
• The powertrain control module (PCM)

Changing the Passlock™ Components
The following components contain codes or passwords, or must learn codes or passwords for the Passlock™ System to allow the vehicle to start:
• The ignition lock cylinder case
• The body control module (BCM)
• The powertrain control module (PCM)
If any of these parts are replaced, a learn procedure must be performed. Refer to Programming Theft Deterrent System Components . If parts are replaced and a learn procedure is not performed, the engine will crank and will not run or will start and stall immediately.
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Sep 22, 2018 • Cars & Trucks
0helpful
1answer

I have tried all the tricks and i still cant get my 2000 impala to start because of the security system.HELP
How do you know it's the security system ? Light lit on the insturment cluster ? If it is there are DTC'S - diagnostic trouble codes stored in the BCM - body control module . There are no tricks , have codes checked do the diagnostics for that code , fix the problem an it will start .
The vehicle theft deterrent (VTD) functions are provided by the Passlock system. Passlock consists of the following components:
• A standard ignition key
• An ignition lock cylinder assembly, including a Passlock sensor
• The body control module (BCM)
• The powertrain control module (PCM).
The Passlock sensor contains a magnet on the lock cylinder and a hall effect switch on the surrounding assembly. When you rotate this cylinder using an ignition key with the proper mechanical cut, the magnet on the lock cylinder activates the hall effect switch. When activated, the Passlock sensor provides a unique resistance value to the Passlock data circuit of the BCM. The resulting voltage is measured by the BCM. This voltage value is compared to one stored in memory (a learned value). If the Passlock data voltage value matches the learned value, the BCM sends a password, via the class 2 serial data link, to the PCM. The PCM compares this value to one stored in memory (a learned password). If the passwords match, the PCM enables engine starting.

DTC B2947 Security System Sensor Power CKT Low
DTC B2948 Security System Sensor Power CKT High
DTC B2957 Security System Sensor Data Circuit Low
DTC B2958 Security System Sensor Data Circuit High
DTC B2960 Sec Sys Sensor Data Incorrect but Valid
DTC B3031 Security System Controller in Learn Mode
DTC B3033 Security System Indicates Tamper

Do yourself a favor , take it to a qualified repair shop .
Read full answer
Jun 26, 2017 • Cars & Trucks
0helpful
1answer

Why is my security light coming on in my 03' chevy impala when driving im scared it will stop on me when doin tht
Hard to say why the light comes on , may have a diagnostic trouble code stored in the BCM - body control module ! Do you have a bunch of other key's on the same ring as the vehicle key ?
Passlock™ System
The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent system prevents the vehicle operation if the correct key is not used in order to start the vehicle. The ignition key turns the ignition lock cylinder. The cylinder rotation produces an analog voltage code in the Passlock™ sensor. This voltage code is received by the BCM. The BCM compares the voltage code to the previously learned voltage code. If the codes match, a class 2 message is sent from the BCM to the powertrain control module (PCM). The message enables the fuel injectors and the crank relay.
The design of the Passlock™ system is to prevent vehicle theft by disabling the engine unless the ignition lock cylinder rotates properly by engaging the correct ignition key. The system is similar in concept to the passkey system. However, the Passlock™ system eliminates the need for a key mounted resistor pellet. The components of the Passlock™ system are as follows:
• The ignition lock cylinder
• The ignition switch
• The Passlock™ sensor
• The body control module (BCM)
• The SECURITY indicator
• The powertrain control module (PCM)
When anyone of these codes set the BCM will turn on the SECURITY light !
DTC B2947
DTC B2948
DTC B2957
DTC B2958
DTC B2960
DTC B3031
DTC B3033
DTC P1626
DTC P1629
DTC P1630
DTC P1631

Your best bet , take it to a qualified repair shop an have it checked !Here are some reasons for the light to come on .
Conditions for Setting the DTC
The BCM detects a short to ground on the Passlock sensor power circuit for 1 second, with the ignition switch in the ACCESSORY, ON, or START position.
The PCM has detected a loss of the state of health serial data message from the theft deterrent system.
Read full answer
May 29, 2017 • Cars & Trucks
0helpful
1answer

My 05 Chevy 2500HD 6.0L won't start. I replaced the fuel pump before i realized the security light was on. I understand this to be an anti theft system. How can i dactivate it so my truck will start? I...
Do you have a second key ?
Passlock™ System
The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent is provided in order to prevent vehicle operation if the correct key is not used in order to start the vehicle. The ignition key turns the lock cylinder. The cylinder rotation produces an analog voltage code in the Passlock™ sensor. This voltage code is received by the BCM. The BCM compares the voltage code to the previously learned voltage code. If the codes match, a class 2 message is sent from the BCM to the powertrain control module (PCM)/vehicle control module (VCM). The message enables the fuel injectors.
The design of the Passlock™ system is to prevent vehicle theft by disabling the engine unless the ignition lock cylinder rotates properly by engaging the correct ignition key. The system is similar in concept to the PASS-Key® system. However, the Passlock™ system eliminates the need for a key mounted resistor pellet. The components of the Passlock™ system are as follows:
• The ignition lock cylinder
• The ignition switch
• The Passlock™ sensor
• The BCM
• The security telltale
• The VCM/PCM

Your best bet , take it to a qualified repair shop . Security light on - DTC'S - diagnostic trouble codes are stored . Having codes check would point in a diagnostic procedure to fix the issue .

DTC B2947
DTC B2948
DTC B2957
DTC B2958
DTC B2960
DTC B3031
DTC B3033
DTC P1626
DTC P1631
Circuit Description
The Passlock™ system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to rotate or the ignition switch is operated while separated from the ignition lock cylinder case. The body control module (BCM) provides security system sensor power and low reference for the Passlock™ sensor. The BCM also measures the security system sensor voltage.
When the correct key is used to start the vehicle, a magnet on the lock cylinder passes close to the Passlock™ sensor within the ignition lock cylinder case. The magnet activates the security hall effect sensor in the Passlock™ sensor which completes a circuit from the security sensor signal circuit through a resistor to the security sensor low reference circuit. The resistance value will vary from vehicle to vehicle. The BCM will measure the voltage on the security sensor signal circuit and compare this voltage to a previously learned voltage. If the voltage measured is within the valid range, the BCM will send a class 2 message to the powertrain control module (PCM) to enable vehicle starting. If the voltage measured is not within the valid range, a class 2 message will be sent to the PCM to disable starting of the vehicle.
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Jan 31, 2018 • 1997 Chevrolet C2500
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1answer

I need to see if there is any way to bypass the security pass switch in the ignition lock on a 2005 Chevy Impala
nope theft security system is part of the bcm and pcm,no way to bypass,it will disable car so you cant crank it.
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Apr 07, 2011 • Chevrolet Impala Cars & Trucks
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Hi i own a 2002 chevy impala LS3800 and at night my dashboard lights go out and darken aswell my engine light stays on and security and battery light flash, i've charged my new battery overnight in hopes...
HAVE VECHICLE CODE SCAN.SEE WHAT CHECK ENGINE LIGHT CODE YOU ARE GETTING.
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Mar 18, 2011 • 2002 Chevrolet Impala
0helpful
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Dono star inicion
WHEN YOU SEE SECURITY WARNING LIGHT.YOUR IS BCM FAULTY OR IGNITION KEY OR IGNITION SWITCH IS WORN UNTIL A POINT WHERE THE BCM AND THE PCM DONT RECOGNIZE THE KEY OR IGNITION SWITCH.SO IT GOES INTO SECURITY MODE THINKING CAR BEING STOLEN.CAUSING SECURITY LIGHT TO COME ON.THIS IS A DEALERSHIP FIX.NOT CHEAP FIX.COST $500.00 THEY WILL HAVE TO GO IN DASH.IF ITS YOUR BCM. BUT THE DEALERSHIP HAS REPLACE BCM OR IGNITION KEY AND SWITCH.THEY WILL HAVE TO REPROGRAM THEM TO THE BCM AND PCM SO YOUR CAR WILL START AGAIN.
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Mar 03, 2010 • 1999 Oldsmobile Alero
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1answer

The security light comes on after u turn the car off for 10 mins and then try to start it is there any ways to fix it of turn the security light off
MOST OF THE TIME YOUR BCM GOES BAD OR THE KEYS ARE WORN UNTIL THE BCM AND PCM DONT RECOGNIZE THEM CAUSING CAR TO GO IN SECURITY THEFT MODE.SO THE KEYS AND IGNITION SWITCH AND BCM HAS TO BE REPLACED AND REPROGRAM.THIS IS DEALERSHIP FIX.BECAUSE THEY HAVE TO USE A SCANNER TO REPROGRAM NEW KEYS AND IGNITION SWITCH TO THE BCM AND PCM SO CAR WILL START.
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Feb 20, 2010 • 1999 Oldsmobile Alero
1helpful
1answer

MY 2002 CHEVY IMPALA 3.4 DRIVE FOR A WHILE THEN SHUTS OFF
Sounds like an altinator problem. Have it checked out. If your altinator is bad it will not recharge your battery while its running and cause your car to lose all electrical power. When this happens, your car will not usually run for more than 10minutes or so.
Read full answer
Mar 22, 2009 • 2002 Chevrolet Impala
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