Technical Support

30 Dec 2009

Battery drain on 2008 and newer GM vehicles with CAN-SL2/CAN-SL-PL.

Symptom

The battery gets drained during cold weather on 2008 and newer GM vehicles when using either a CAN-SL2 or CAN-SL-PL.

Cause

This situation occurs when the vehicle is not being used regularly during cold temperatures. The additional battery consumption is caused by the module on the factory immobilizer circuit. The factory immobilizer on GM vehicles must be constantly energised in order to perform an immobilizer bypass during remote-start. The module requires an idle-current of 3mA with all vehicles, but requires an additional constant 25mA to energise this circuit.

30mA - Vehicles idle current draw (average)
+20mA - Remote Starters idle current draw (average)
+3mA - CAN-SL2/CAN-SL-PL idle current draw
+25mA - CAN-SL2/CAN-SL-PL immobilizer bypass draw
----
78mA - Total constant idle current draw.

78mA of idle current draw can be too high on some vehicles during colder weather if the vehicle is not being driven on a regular basis.

Solution

A passive transponder can be used to bypass the immobilizer in order to reduce the amount of current being consumed by 25mA. The TB-GM2 passive immobilizer bypass can be used in this case.

Using the TB-GM2:

• Install the TB-GM2 and the RF Loop (Ring).
• Reconnect the vehicle wire that was cut at the transponder connector during the CAN-SL2/CAN-SL-PL installation.
• Disconnect the White/Black from the CAN-SL2/CAN-SL-PL. The Pink wire from the CAN-SL2/CAN-SL-PL should still be connected to the vehicle wire at the the transponder connector that was reconnected in the previous step.
• Turn the key to the ON position, then turn the key OFF.
• Remote start the vehicle. The TB-GM2 is now programmed.

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