Thought I'd drop this in from the manual...
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 fifteen to twenty-five milliamperes (0.015 to 0.025 ampere) with the ignition switch in the Off position,
and all non-ignition controlled circuits in proper working order. Up to twenty-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-one days, may discharge the battery to an inadequate level. When a vehicle will not be
used for twenty-one days or more (stored), remove the IOD fuse from the Integrated Power Module
(IPM). This will reduce battery discharging.
Excessive IOD can be caused by:
² Electrical items left on.
² Faulty or improperly adjusted switches.
² Faulty or shorted electronic modules and components.
² An internally shorted generator.
² Intermittent shorts in the wiring.
If the IOD is over twenty-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 twenty minutes.
(2) Disconnect the battery negative cable.
(3) Set an electronic digital multi-meter to its highest amperage scale. Connect the multi-meter between the disconnected battery negative cable terminal
clamp and the battery negative terminal post. Make sure that the doors remain closed so that the illuminated entry system is not activated. The multimeter
amperage reading may remain high for up to three minutes, or may not give any reading at all while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The multi-meter leads must be securely clamped to the battery negative cable terminal clamp and the battery
negative terminal post. If continuity between the battery negative terminal post and the negative cable terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated and all of the tests will have to be repeated.
(4) After about three minutes, the high-amperage IOD reading on the multi-meter should become very low or non existent, depending upon the electrical
equipment in the vehicle. If the amperage reading remains high, remove and replace each fuse or circuit breaker in the Integrated Power Module (IPM), one
at a time until the amperage reading becomes very low, or non existent. Refer to the appropriate wiring information for complete Integrated Power Module
fuse, circuit breaker, and circuit identification. This will isolate each circuit and identify the circuit that is the source of the high-amperage IOD. If the
amperage reading remains high after removing and replacing each fuse and circuit breaker, disconnect the wire harness from the generator. If the amperage
reading now becomes very low or non existent, (Refer to 8 - ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) for the proper charging system diagnosis
and testing procedures. After the high-amperage IOD has been corrected, switch the multi-meter to progressively lower amperage scales and, if necessary,
repeat the fuse and circuit breaker remove-and-replace process to identify and correct all sources of excessive IOD. It is now safe to select the lowest milliampere
scale of the multi-meter to check the low amperage IOD.
CAUTION: Do not open any doors, or turn on any electrical accessories with the lowest milliampere scale selected, or the multi-meter may be damaged.
(5) Allow twenty minutes for the IOD to stabilize and observe the multi-meter reading. The low-amperage IOD should not exceed twenty-five milliamperes
(0.025 ampere). If the current draw exceeds twenty five milliamperes, isolate each circuit using the fuse and circuit breaker remove-and-replace process in
Step 4. The multi-meter reading will drop to within the acceptable limit when the source of the excessive current draw is disconnected. Repair this circuit as required;
Hi there!
Yes - are you any good at car maintenance?
Read the vehicle assistance section of the forum to get an idea of the little foibles it will quite likely present you!
Cheers! Nev
