Key fob not working.
Thread Starter
Advanced
Joined: Sep 2023
Posts: 90
Likes: 7
From: Riverside
Key fob not working.
Hello I have a c6 base with 60k miles ( if you wanted details) so 2 days ago I somehow left my keys on the car and drove off thankfully I found my keys but the keys to the vette are gone. I used my spare to start it using the glove box trick and worked took it home and called it a night. Following day I started it up again using the same thing and it turned on great. Went to where I had to go was able to leave that spot back home using the same method. When I got home I tried to program my key doing the window, glove box and truck open. I did this about 2 times and failed every time. (I only have 1 key to program as of right now, other one comes in Monday.) since it didn’t work I just decided to call it and I wanted to park up the vette in a better spot and roll up my windows. After trying to use the glove box method to just move the car it no longer starts by putting it in the glove box. I’m already planning on calling a locksmith to program the keys once the other one gets here but my windows are still down. Any tips or ideas on what I can do to save myself money and time?
Always greatly appreciated for those who reply. THANK YOU!
Always greatly appreciated for those who reply. THANK YOU!
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,620
Likes: 4,066
From: Cape Coral, Florida
Did you replace the battery in the spare FOB ??...if it has been years since using it it's probably dead...as long as the FOB is OK with the dead FOB battery it should still start when placed in the back up slot...to start the car whether with a good functioning FOB or not the back up antenna MUST be good...or the AC voltage (less than 1 volt) signal going to the antenna is not there which may be a bad RCDLR....make sure the battery is around 3.2 volts.
Thread Starter
Advanced
Joined: Sep 2023
Posts: 90
Likes: 7
From: Riverside
Did you replace the battery in the spare FOB ??...if it has been years since using it it's probably dead...as long as the FOB is OK with the dead FOB battery it should still start when placed in the back up slot...to start the car whether with a good functioning FOB or not the back up antenna MUST be good...or the AC voltage (less than 1 volt) signal going to the antenna is not there which may be a bad RCDLR....make sure the battery is around 3.2 volts.
Yes I bought a new pack of 2032 batteries and it’s strange that it doesn’t work anymore because I turned the car on 3 times using that method and now it doesn’t even work so I’m lost. You think i hsould check the antenna?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,620
Likes: 4,066
From: Cape Coral, Florida
Well those batteries could have been sitting in the store for a while so if you have a DVOM check the voltage first…it’s funny how the FOB worked in the back up antenna slot but not now…do you hear any “clicks” coming from the RCDLR when pushing the start button ??…to satisfy my own curiosity last year I removed the antenna and with my good FOB and with my spare FOB with no FOB battery installed the car did not start with the back up antenna removed…I took the antenna out of the garage and the car did start a few times and then a no start…you said yours started 3x’s and then a no start.
Last edited by C5 Diag; Mar 30, 2025 at 01:31 PM.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,620
Likes: 4,066
From: Cape Coral, Florida
Service Info for your 2013...of the 4 antennas only 3 are used for passive entry...the last being the 'back up' which is only used for starting...I've read some info on here that states that 2 antennas are required for start...only 1 needed !!
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Immobilizer Description and Operation
Immobilizer System
The immobilizer system is incorporated into the remote control door lock receiver (RCDLR). The immobilizer is provided in order to prevent the vehicle operation if an incorrect or unprogrammed keyless entry transmitter is used in an attempt to start the vehicle. When the ignition button is pressed, the backup keyless entryantenna broadcasts a challenge to the transmitter. Both the RCDLR and the transmitter perform a calculation based on this challenge. The transmitter will transmit its calculation result to the RCDLR via radio frequency (RF). If both calculations match, vehicle starting will be allowed. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).
The design of the immobilizer system is to prevent vehicle theft by disabling the engine unless the correct transmitter is present when attempting to start the vehicle. The system is similar in concept to conventional immobilizer system which use a normal vehicle key. The components of the immobilizer system are as follows:
* The start button
* The #1-#4 keyless entry transmitters
* The backup keyless entry antenna
* The body control module (BCM)
* The RCDLR
* The security indicator
* The ECM
Start Button
The start button is located at the right side of the steering column, on the instrument panel. The start button is used to start the vehicle engine, turn OFF the vehicle, put the vehicle in ACC mode, or put the vehicle in RUN mode.
The start button signals the body control module (BCM) to ground the Run/Crank control relay which will then feed power to the Crank relay in the under hood fuse block. The BCM also simultaneously send a serial data message to the engine control module (ECM) to ground the starter enable relay to allow power to the starter solenoid and starter motor.
Keyless Entry Transmitters
The keyless entry transmitters are not only used to passively or actively lock and unlock the vehicle, they are also used to allow vehicle starting. If the remote control door lock receiver (RCDLR) does not receive a valid RF response after the transmitter is challenged, the RCDLR will not send a fuel enable message to the engine control module (ECM). If the RCDLR is unable to establish communication with the transmitter during an attempted engine start, the NO FOB DETECTED message will display on the driver information center (DIC).
When any one of the 4 allowable programmed key fobs are challenged by pressing the start button, they will passively send a RF signal to the RCDLR. The RCDLR will then send a serial data message to the engine control module (ECM) to enable engine starting.
Keyless Entry Antenna - Backup
The backup keyless entry antenna is located in the glove box area. It has a small pocket next to it where the transmitter can be inserted if the transmitter battery is dead, weak, or the RF signal is being interrupted.
The purpose of the backup keyless entry antenna is to send a low frequency RF challenge to a programmed transmitter within the interior of the vehicle when the start button is pressed. The backup keyless entry antenna is controlled by the remote control door lock receiver (RCDLR).
Body Control Module (BCM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the BCM as a gateway in order to communicate.
The body control module is a multi-function module. The body control module (BCM) is used in the immobilizer system as a gateway for the RCDLR to send a fuel enable message to the ECM.
Remote Control Door Lock Receiver (RCDLR)
Important:
The RCDLR does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the body control module (BCM) as a gateway in order to communicate.
The backup keyless entry antenna is controlled by the RCDLR. The RCDLR also controls three other low frequency antennas used for passive vehicle entry, but not for immobilizer operations. The RCDLR will send an AC voltage signal and provide ground to the backup keyless entry antenna when the ignition button is pressed. This will enable the backup keyless entry antenna to send out a low frequency broadcast challenge to a transmitter. The RCDLR also has an internal radio frequency (RF) antenna to receive the transmitters passively or actively sent responses. The RCDLR is responsible for sending the fuel enable message to the ECM if all the requirements are met.
Security Indicator
The security indicator appears on the instrument cluster. If the security indicator flashes or is illuminated continuously during vehicle operation, a malfunction exists within the immobilizer system. The security indicator is a dual purpose indicator. With the ignition OFF, the indicator it is controlled by the body control module (BCM) as a status indicator for the content theft deterrent system. With the ignition ON, it is controlled by the immobilizer system as a fault indicator.
Engine Control Module (ECM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the ECM use the body control module (BCM) as a gateway in order to communicate.
The ECM communicates with the BCM and the RCDLR over the serial data line. If the RCDLR receives a valid transmitter RF response, the RCDLR will send the fuel enable message to the ECM to enable the starting system. If the RCDLR does not receive a valid response from the transmitter, the RCDLR will send the fuel disable message, indicating to the ECM that vehicle starting should not be allowed. Additionally, if the fuel enable password received by the ECM does match the stored password, vehicle starting will be disabled.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Immobilizer Description and Operation
Immobilizer System
The immobilizer system is incorporated into the remote control door lock receiver (RCDLR). The immobilizer is provided in order to prevent the vehicle operation if an incorrect or unprogrammed keyless entry transmitter is used in an attempt to start the vehicle. When the ignition button is pressed, the backup keyless entryantenna broadcasts a challenge to the transmitter. Both the RCDLR and the transmitter perform a calculation based on this challenge. The transmitter will transmit its calculation result to the RCDLR via radio frequency (RF). If both calculations match, vehicle starting will be allowed. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).
The design of the immobilizer system is to prevent vehicle theft by disabling the engine unless the correct transmitter is present when attempting to start the vehicle. The system is similar in concept to conventional immobilizer system which use a normal vehicle key. The components of the immobilizer system are as follows:
* The start button
* The #1-#4 keyless entry transmitters
* The backup keyless entry antenna
* The body control module (BCM)
* The RCDLR
* The security indicator
* The ECM
Start Button
The start button is located at the right side of the steering column, on the instrument panel. The start button is used to start the vehicle engine, turn OFF the vehicle, put the vehicle in ACC mode, or put the vehicle in RUN mode.
The start button signals the body control module (BCM) to ground the Run/Crank control relay which will then feed power to the Crank relay in the under hood fuse block. The BCM also simultaneously send a serial data message to the engine control module (ECM) to ground the starter enable relay to allow power to the starter solenoid and starter motor.
Keyless Entry Transmitters
The keyless entry transmitters are not only used to passively or actively lock and unlock the vehicle, they are also used to allow vehicle starting. If the remote control door lock receiver (RCDLR) does not receive a valid RF response after the transmitter is challenged, the RCDLR will not send a fuel enable message to the engine control module (ECM). If the RCDLR is unable to establish communication with the transmitter during an attempted engine start, the NO FOB DETECTED message will display on the driver information center (DIC).
When any one of the 4 allowable programmed key fobs are challenged by pressing the start button, they will passively send a RF signal to the RCDLR. The RCDLR will then send a serial data message to the engine control module (ECM) to enable engine starting.
Keyless Entry Antenna - Backup
The backup keyless entry antenna is located in the glove box area. It has a small pocket next to it where the transmitter can be inserted if the transmitter battery is dead, weak, or the RF signal is being interrupted.
The purpose of the backup keyless entry antenna is to send a low frequency RF challenge to a programmed transmitter within the interior of the vehicle when the start button is pressed. The backup keyless entry antenna is controlled by the remote control door lock receiver (RCDLR).
Body Control Module (BCM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the BCM as a gateway in order to communicate.
The body control module is a multi-function module. The body control module (BCM) is used in the immobilizer system as a gateway for the RCDLR to send a fuel enable message to the ECM.
Remote Control Door Lock Receiver (RCDLR)
Important:
The RCDLR does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the body control module (BCM) as a gateway in order to communicate.
The backup keyless entry antenna is controlled by the RCDLR. The RCDLR also controls three other low frequency antennas used for passive vehicle entry, but not for immobilizer operations. The RCDLR will send an AC voltage signal and provide ground to the backup keyless entry antenna when the ignition button is pressed. This will enable the backup keyless entry antenna to send out a low frequency broadcast challenge to a transmitter. The RCDLR also has an internal radio frequency (RF) antenna to receive the transmitters passively or actively sent responses. The RCDLR is responsible for sending the fuel enable message to the ECM if all the requirements are met.
Security Indicator
The security indicator appears on the instrument cluster. If the security indicator flashes or is illuminated continuously during vehicle operation, a malfunction exists within the immobilizer system. The security indicator is a dual purpose indicator. With the ignition OFF, the indicator it is controlled by the body control module (BCM) as a status indicator for the content theft deterrent system. With the ignition ON, it is controlled by the immobilizer system as a fault indicator.
Engine Control Module (ECM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the ECM use the body control module (BCM) as a gateway in order to communicate.
The ECM communicates with the BCM and the RCDLR over the serial data line. If the RCDLR receives a valid transmitter RF response, the RCDLR will send the fuel enable message to the ECM to enable the starting system. If the RCDLR does not receive a valid response from the transmitter, the RCDLR will send the fuel disable message, indicating to the ECM that vehicle starting should not be allowed. Additionally, if the fuel enable password received by the ECM does match the stored password, vehicle starting will be disabled.
Last edited by C5 Diag; Mar 30, 2025 at 04:48 PM.
Thread Starter
Advanced
Joined: Sep 2023
Posts: 90
Likes: 7
From: Riverside
Immobilizer Description and Operation
Immobilizer System
The immobilizer system is incorporated into the remote control door lock receiver (RCDLR). The immobilizer is provided in order to prevent the vehicle operation if an incorrect or unprogrammed keyless entry transmitter is used in an attempt to start the vehicle. When the ignition button is pressed, the backup keyless entryantenna broadcasts a challenge to the transmitter. Both the RCDLR and the transmitter perform a calculation based on this challenge. The transmitter will transmit its calculation result to the RCDLR via radio frequency (RF). If both calculations match, vehicle starting will be allowed. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).
The design of the immobilizer system is to prevent vehicle theft by disabling the engine unless the correct transmitter is present when attempting to start the vehicle. The system is similar in concept to conventional immobilizer system which use a normal vehicle key. The components of the immobilizer system are as follows:
* The start button
* The #1-#4 keyless entry transmitters
* The backup keyless entry antenna
* The body control module (BCM)
* The RCDLR
* The security indicator
* The ECM
Start Button
The start button is located at the right side of the steering column, on the instrument panel. The start button is used to start the vehicle engine, turn OFF the vehicle, put the vehicle in ACC mode, or put the vehicle in RUN mode.
The start button signals the body control module (BCM) to ground the Run/Crank control relay which will then feed power to the Crank relay in the under hood fuse block. The BCM also simultaneously send a serial data message to the engine control module (ECM) to ground the starter enable relay to allow power to the starter solenoid and starter motor.
Keyless Entry Transmitters
The keyless entry transmitters are not only used to passively or actively lock and unlock the vehicle, they are also used to allow vehicle starting. If the remote control door lock receiver (RCDLR) does not receive a valid RF response after the transmitter is challenged, the RCDLR will not send a fuel enable message to the engine control module (ECM). If the RCDLR is unable to establish communication with the transmitter during an attempted engine start, the NO FOB DETECTED message will display on the driver information center (DIC).
When any one of the 4 allowable programmed key fobs are challenged by pressing the start button, they will passively send a RF signal to the RCDLR. The RCDLR will then send a serial data message to the engine control module (ECM) to enable engine starting.
Keyless Entry Antenna - Backup
The backup keyless entry antenna is located in the glove box area. It has a small pocket next to it where the transmitter can be inserted if the transmitter battery is dead, weak, or the RF signal is being interrupted.
The purpose of the backup keyless entry antenna is to send a low frequency RF challenge to a programmed transmitter within the interior of the vehicle when the start button is pressed. The backup keyless entry antenna is controlled by the remote control door lock receiver (RCDLR).
Body Control Module (BCM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the BCM as a gateway in order to communicate.
The body control module is a multi-function module. The body control module (BCM) is used in the immobilizer system as a gateway for the RCDLR to send a fuel enable message to the ECM.
Remote Control Door Lock Receiver (RCDLR)
Important:
The RCDLR does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the body control module (BCM) as a gateway in order to communicate.
The backup keyless entry antenna is controlled by the RCDLR. The RCDLR also controls three other low frequency antennas used for passive vehicle entry, but not for immobilizer operations. The RCDLR will send an AC voltage signal and provide ground to the backup keyless entry antenna when the ignition button is pressed. This will enable the backup keyless entry antenna to send out a low frequency broadcast challenge to a transmitter. The RCDLR also has an internal radio frequency (RF) antenna to receive the transmitters passively or actively sent responses. The RCDLR is responsible for sending the fuel enable message to the ECM if all the requirements are met.
Security Indicator
The security indicator appears on the instrument cluster. If the security indicator flashes or is illuminated continuously during vehicle operation, a malfunction exists within the immobilizer system. The security indicator is a dual purpose indicator. With the ignition OFF, the indicator it is controlled by the body control module (BCM) as a status indicator for the content theft deterrent system. With the ignition ON, it is controlled by the immobilizer system as a fault indicator.
Engine Control Module (ECM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the ECM use the body control module (BCM) as a gateway in order to communicate.
The ECM communicates with the BCM and the RCDLR over the serial data line. If the RCDLR receives a valid transmitter RF response, the RCDLR will send the fuel enable message to the ECM to enable the starting system. If the RCDLR does not receive a valid response from the transmitter, the RCDLR will send the fuel disable message, indicating to the ECM that vehicle starting should not be allowed. Additionally, if the fuel enable password received by the ECM does match the stored password, vehicle starting will be disabled.
Immobilizer System
The immobilizer system is incorporated into the remote control door lock receiver (RCDLR). The immobilizer is provided in order to prevent the vehicle operation if an incorrect or unprogrammed keyless entry transmitter is used in an attempt to start the vehicle. When the ignition button is pressed, the backup keyless entryantenna broadcasts a challenge to the transmitter. Both the RCDLR and the transmitter perform a calculation based on this challenge. The transmitter will transmit its calculation result to the RCDLR via radio frequency (RF). If both calculations match, vehicle starting will be allowed. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).
The design of the immobilizer system is to prevent vehicle theft by disabling the engine unless the correct transmitter is present when attempting to start the vehicle. The system is similar in concept to conventional immobilizer system which use a normal vehicle key. The components of the immobilizer system are as follows:
* The start button
* The #1-#4 keyless entry transmitters
* The backup keyless entry antenna
* The body control module (BCM)
* The RCDLR
* The security indicator
* The ECM
Start Button
The start button is located at the right side of the steering column, on the instrument panel. The start button is used to start the vehicle engine, turn OFF the vehicle, put the vehicle in ACC mode, or put the vehicle in RUN mode.
The start button signals the body control module (BCM) to ground the Run/Crank control relay which will then feed power to the Crank relay in the under hood fuse block. The BCM also simultaneously send a serial data message to the engine control module (ECM) to ground the starter enable relay to allow power to the starter solenoid and starter motor.
Keyless Entry Transmitters
The keyless entry transmitters are not only used to passively or actively lock and unlock the vehicle, they are also used to allow vehicle starting. If the remote control door lock receiver (RCDLR) does not receive a valid RF response after the transmitter is challenged, the RCDLR will not send a fuel enable message to the engine control module (ECM). If the RCDLR is unable to establish communication with the transmitter during an attempted engine start, the NO FOB DETECTED message will display on the driver information center (DIC).
When any one of the 4 allowable programmed key fobs are challenged by pressing the start button, they will passively send a RF signal to the RCDLR. The RCDLR will then send a serial data message to the engine control module (ECM) to enable engine starting.
Keyless Entry Antenna - Backup
The backup keyless entry antenna is located in the glove box area. It has a small pocket next to it where the transmitter can be inserted if the transmitter battery is dead, weak, or the RF signal is being interrupted.
The purpose of the backup keyless entry antenna is to send a low frequency RF challenge to a programmed transmitter within the interior of the vehicle when the start button is pressed. The backup keyless entry antenna is controlled by the remote control door lock receiver (RCDLR).
Body Control Module (BCM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the BCM as a gateway in order to communicate.
The body control module is a multi-function module. The body control module (BCM) is used in the immobilizer system as a gateway for the RCDLR to send a fuel enable message to the ECM.
Remote Control Door Lock Receiver (RCDLR)
Important:
The RCDLR does not communicate on the GM LAN high speed bus. The RCDLR and the engine control module (ECM) use the body control module (BCM) as a gateway in order to communicate.
The backup keyless entry antenna is controlled by the RCDLR. The RCDLR also controls three other low frequency antennas used for passive vehicle entry, but not for immobilizer operations. The RCDLR will send an AC voltage signal and provide ground to the backup keyless entry antenna when the ignition button is pressed. This will enable the backup keyless entry antenna to send out a low frequency broadcast challenge to a transmitter. The RCDLR also has an internal radio frequency (RF) antenna to receive the transmitters passively or actively sent responses. The RCDLR is responsible for sending the fuel enable message to the ECM if all the requirements are met.
Security Indicator
The security indicator appears on the instrument cluster. If the security indicator flashes or is illuminated continuously during vehicle operation, a malfunction exists within the immobilizer system. The security indicator is a dual purpose indicator. With the ignition OFF, the indicator it is controlled by the body control module (BCM) as a status indicator for the content theft deterrent system. With the ignition ON, it is controlled by the immobilizer system as a fault indicator.
Engine Control Module (ECM)
Important:
The remote control door lock receiver (RCDLR) does not communicate on the GM LAN high speed bus. The RCDLR and the ECM use the body control module (BCM) as a gateway in order to communicate.
The ECM communicates with the BCM and the RCDLR over the serial data line. If the RCDLR receives a valid transmitter RF response, the RCDLR will send the fuel enable message to the ECM to enable the starting system. If the RCDLR does not receive a valid response from the transmitter, the RCDLR will send the fuel disable message, indicating to the ECM that vehicle starting should not be allowed. Additionally, if the fuel enable password received by the ECM does match the stored password, vehicle starting will be disabled.
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Thread Starter
Advanced
Joined: Sep 2023
Posts: 90
Likes: 7
From: Riverside
Hello I have a c6 base with 60k miles ( if you wanted details) so 2 days ago I somehow left my keys on the car and drove off thankfully I found my keys but the keys to the vette are gone. I used my spare to start it using the glove box trick and worked took it home and called it a night. Following day I started it up again using the same thing and it turned on great. Went to where I had to go was able to leave that spot back home using the same method. When I got home I tried to program my key doing the window, glove box and truck open. I did this about 2 times and failed every time. (I only have 1 key to program as of right now, other one comes in Monday.) since it didn’t work I just decided to call it and I wanted to park up the vette in a better spot and roll up my windows. After trying to use the glove box method to just move the car it no longer starts by putting it in the glove box. I’m already planning on calling a locksmith to program the keys once the other one gets here but my windows are still down. Any tips or ideas on what I can do to save myself money and time?
Always greatly appreciated for those who reply. THANK YOU!
Always greatly appreciated for those who reply. THANK YOU!