Quiescent Drain (G1451124)

Loading...

If a customer complains of a startup battery that discharges continuously or when left for a prolonged period of time, it is recommended that a quiescent drain test is done as described below.

When the vehicle is armed, the effect of the security system status indicator flashing is to cause a pulsation in the measured current drain. In this case, either the average current should be taken (using a digital multimeter with an averaging system) or the current reading taken, ignoring the brief high current peaks.

Preparation - All Vehicles, Using a Digital Multimeter With a Current Clamp

1. Switch off all electrical loads and make sure that the vehicle is in Power Mode 4 (vehicle unlocked and smart key present).
2. Remove any other potential electrical drains such as accessories plugged into accessory sockets.
3. Connect the current clamp to the digital multimeter.
4. Calibrate the current clamp.
5. Install the current clamp around the startup battery ground cable.
6. Follow the instructions in the "Quiescent Current Test" section in this procedure.

Quiescent Current Test

1. Select Power Mode 6 (Ignition ON) and then select Power Mode 4 (vehicle unlocked and smart key present) (do not crank).
2. Remove key from ignition switch (if equipped).
3. Open and latch all doors, hood, tailgate.
4. Lock the vehicle using the remote function on the remote device or on the smart key (Single lock only to avoid volumetric sensor arming).
5. Wait until the vehicle systems have completely shut down.
   • The hazard warning lamp switch illumination or the Light Emitting Diode (LED), installed in the switch is a possible indicator of the shutdown period. When the Body Control Module (BCM)/Gateway Module A (GWM) shutdown has completed, the illumination of the hazard warning lamp switch or the LED extinguishes.
   • If none of the above listed indicators are available, wait until the specified time for shutdown period has elapsed. Refer to the 'Quiescent Drain - Typical Values' section in this procedure for details.
6. Record the amperage readings.
7. Record the final reading on the battery report form.

The preferred method of testing following an excessive current consumption figure is to use a current clamp around individual junction box leads to the various suspected circuits to identify a potential cause.

This is in preference to the old method of removing fuses for the following reasons:

• The drain may be caused by a module remaining active and preventing the quiescent drain from reducing to normal levels.
• The drain may be caused by a relay winding that is activated. Pulling the fuse can allow this to ‘reset’ and the drain will be lost and go un-diagnosed.

The total current drain will be higher if certain approved accessories are installed. For example: tracker, trailer module.