cdinwiddie

I have a bcm that won't wake up out of sleep mode. I rigged an auxillary switch to cut the power on and off so I don't have to disconnect the battery everytime. However, now the bcm goes to sleep within like 5 minutes. I found a used bcm out of the exact same optioned and year vette as mine. Will I just have to do the bcm relearn or will I still need the tech II to enter in all the options of my car? thanks

Kevin Kuse

BCM Wake-Up/Sleep State


The BCM is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the BCM to wake-up when activated or deactivated. Multiple switch wake-ups are needed in order to sense both the insertion and the removal of the ignition key. This would allow the BCM to enter a sleep state when the key is IN or OUT of the ignition.

The BCM will enter a wake-up state if any of the following wake-up inputs are detected:


Any activity on the serial data line
Hatch ajar switch
Hatch release switch
Door ajar switch
Key-in-ignition switch
Monitored load relay
Parking/fog/headlamps are on
The BCM experiences a battery disconnect and reconnect condition.
The ignition is turned ON.
The BCM will enter a sleep state when all of the following conditions exist:


No activity exists on the serial data line.
The ignition switch is OFF.
No outputs are commanded.
No delay timers are actively counting.
No wake-up inputs are present.
If all these conditions are met the BCM will enter a low power or sleep condition. This condition would indicate the BCM, which is the power mode master of the vehicle, must have sent a message to the other systems on the serial data line to stop broadcasting their state of health messages.

Power Requirements
The BCM has two main power feeds (high and low current), and two main grounds. The low power feed (battery 1) is used to provide power for the BCMs logic and internal driver operation. The high power feed (battery 2) is used to provide power for systems that draw higher amounts of current (motors, lights, etc.). Operating current at the BCMs battery should not exceed 3.0 amperes at battery 1, and 7.5 amperes (for 2 seconds ) at battery 2 while the BCM is awake, and 2.5 milliamps when the BCM is asleep. For most BCM functions, the BCM will operate properly with a system voltage of 9.0-16.0 volts . If system voltages exceed 16.0 volts the BCM will provide protection by disabling certain functions that may damage due to higher than normal system voltages.

Kevin Kuse

Important : Before proceeding with this programming procedure, check for proper communications between the BCM and PCM. If communications cannot be established, refer to the appropriate Diagnostic System Check for the system unable to communicate.

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.

Manual Programming (Domestic/ Canada Only)



Using a Tech 2, select New BCM Setup and program the BCM with the correct RPO code configuration.
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. If the engine does not start, Refer to the Diagnostic System Check See: Powertrain Management\Computers and Control Systems\Testing and Inspection
Important : Performing this procedure may cause a DTC P1630 to set. If a DTC P1630 sets, turn OFF the ignition for 30 seconds , then turn ON the ignition. If the DTC P1630 does not clear, Refer to Diagnostic System Check See: Powertrain Management\Computers and Control Systems\Testing and Inspection

1stGlance

Hi neighbor!!

I have a 2000 convertible - but I am having problems with the hatch not wanting open without manually pulling the wire to open it - then manually lowering the windows...

I was told the BCM was not sending the signal to the switch for opening the toneau/hatch and lowering the windows - when you push the button - to store the convertible top.

What would you suggest to fix - will I have to replace the BCM
or could some strange problem with the ignition switch cause this problem?
(not having any other ignition switch issues currently)

Any help would be greatly appreciated!!