Ignition Off Draw (IOD) Tests

The content of this article reflects the changes called out by TSB 26-04-99.

IGNITION OFF DRAW (IOD) TESTS

High battery current draw when the ignition switch in the off position will discharge a battery. After a dead battery is serviced, the vehicle Ignition Off Draw (IOD) should be checked. To determine if a high current draw condition exists, check the vehicle with a Digital multimeter that has an ammeter range from at least 10 amps down to 10 milliamps; (30) milliamps is allowable.

1. Verify all electrical accessories are OFF:
- Remove key from ignition switch
- Turn off all lamps
- Trunk compartment lamp is disconnected or removed
- Glove box lamp goes off when the door is closed
- All doors are closed
- Sun visor vanity lamps are OFF

2. Disconnect battery negative remote cable.

CAUTION: Do not operate any accessory that has a greater draw than the ammeter can measure.

3. Using a Digital multi-meter, set to 10 amps and connect leads between the battery negative remote terminal and the battery negative remote cable stud.
a. Remove the "Seat Belt" (20 amp max) AND the "EATX" (20 amp min) fuses from the PDC.
b. Wait 1 minute.
c. If the reading is greater than 30 milliamps, go to HIGH MILLIAMP READING.
d. Reinstall the EATX fuse.
e. If the draw increases, remove the fuse again and immediately reinstall the fuse. If the draw increases again, repeat the remove and install process (2) or (3) times. If the draw continues to increase, it will be necessary to wait for up to (20) minutes to see if the draw drops. If it does not, the problem will be in the EATX module or circuit.
f. If the draw remains under (30) milliamps, there is not a problem with an "Ignition Off Draw". If the draw did increase, it will be necessary to wait for 30 minutes. If it does not, the problem might be with the SCTM or seat belt circuit. Verify SCTM time-out.
g. To enable the SCTM to time-out in 30 seconds, perform the following:
- 4 key cycles within 4 seconds
- Pull radio fuse if RAZ radio equipped (Integrated CD and Cassette)

The diagnostic mode will reflect an unlocked seat belt if the doors are open (door ajar switch closed), and a locked seat belt condition if the doors are closed (door ajar switch open).

NOTE: Each time the ammeter is disconnected and reconnected, all electronic timer functions will be reactivated

High Milliampere Reading

NOTE: Perform BATTERY IGNITION OFF DRAW TEST before proceeding.

If the IOD is high, there is either a short circuit or a fault in an electronic module. There are (6) other fuses in the Power Distribution Center and Junction Block that feed the modules with ignition off draw. Ensure that all electronic timer functions are timed out before testing any of the components.

In the Power Distribution Center
- Ignition Fuel Starter (20 Amp)
- Hazard Flasher (20 Amp)
- EATX (20 Amp min) (previously tested)
- Seat Belt (20 Amp max) (previously tested)
- Stop Lamp (20 Amp)

In the Junction Block:
- Daytime Running Lamps (DRL) (20 Amp)
- Horns-Cigar Lighter (20 Amp)
- Interior lamps (10 Amp) (IOD)
- Park/tail lamps-Instrument Cluster (20 Amp)

NOTE: Do not operate any accessory that has a greater draw than the installed ammeter can measure.

IOD Draw Table:

Replace fuses one at a time. The module should draw a few milliamps when the fuse is replaced. If it draws in excess of (20) milliamps (not including timed out functions) then the module should be replaced or wiring should be investigated. Check for faulty systems operations or module fault codes to help find wiring faults. Be sure you have double checked other possible IOD draws. Refer to IOD Draw Table.

Module Amperage Table:

To determine if a module draw is within acceptable range, refer to the Module Amperage Table for IOD readings.

NOTE: To check to see if SCTM is initialized, pull on the seat belt and if it is locked, the module is not initialized or "Awake".