Ignition-Off Draw Test

The term Ignition-Off Draw (IOD) identifies a normal condition where power is being drained from the battery with the ignition switch in the Off position. A normal vehicle electrical system will draw from five to thirty-five milliamperes (0.005 to 0.035 ampere) with the ignition switch in the Off position, and all non-ignition controlled circuits in proper working order. Up to thirty-five milliamperes are needed to enable the memory functions for the Powertrain Control Module (PCM), digital clock, electronically tuned radio, and other modules which may vary with the vehicle equipment.

A vehicle that has not been operated for approximately twenty days, may discharge the battery to an inadequate level. When a vehicle will not be used for twenty days or more (stored), remove the IOD fuse from the Junction Block (JB). This will reduce battery discharging.

Excessive IOD can be caused by:

• Electrical items left on.
• Inoperative or improperly adjusted switches.
• Inoperative or shorted electronic modules and components.
• An internally shorted generator.
• Intermittent shorts in the wiring.

If the IOD is over thirty-five milliamperes, the problem must be found and corrected before replacing a battery. In most cases, the battery can be charged and returned to service after the excessive IOD condition has been corrected.

1. Verify that all electrical accessories are off. Turn off all lamps, remove the ignition key, and close all doors. If the vehicle is equipped with an illuminated entry system or an electronically tuned radio, allow the electronic timer function of these systems to automatically shut off (time out). This may take up to ten minutes. See the ELECTRONIC MODULE IGNITION-OFF DRAW TABLE for more information.

   ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
   Module	Time Out? (If Yes, Interval And Wake-Up Input)	IOD	IOD After Time Out
   Radio	No	1 to 3 milliamperes	N/A
   Audio Power Amplifier	No	up to 1 milliampere	N/A
   Powertrain Control Module (PCM)	No	0.95 milliampere	N/A

2. Determine that the underhood lamp is operating properly, then disconnect the lamp wire harness connector or remove the lamp bulb.
3. Turn off all electrical accessories.
4. Disconnect the battery negative cable.
   WARNING: Do not open any doors, or turn on any electrical accessories. Failure to do so can result in possible serious or fatal injury.