Electrical - Battery Drain
TSB 06-8-1305/01/06
BATTERY DRAIN - VEHICLES BUILT PRIOR TO
3/24/2006
FORD:
2003-2006 Expedition
LINCOLN:
2003-2006 Navigator
ISSUE
Some 2003-2006 Expedition/Navigator vehicles built before 3/24/2006 may exhibit a dead battery due to excessive key off load (KOL).
ACTION
Refer to the following Service Procedure to isolate the cause of the excessive KOL.
SERVICE PROCEDURE
NOTE
THE KOL VALUES LISTED IN THIS TSB DO NOT INCLUDE AFTERMARKET EQUIPMENT. TO PREVENT MISDIAGNOSIS, IT IS RECOMMENDED TO DISCONNECT ALL AFTERMARKET EQUIPMENT BEFORE PERFORMING A KOL TEST.
Test Setup:
Set the HEADLAMP SWITCH to OFF. Turn the DOME LAMP SWITCH to OFF (dome defeat - dome lamps do not turn on). With the IGNITION SWITCH OFF remove the key from the ignition. Open the hood so that the battery is accessible. Close all doors including liftgate and liftglass.
Disconnect the negative battery terminal (Figure 1). Attach a jumper wire between the negative battery post and negative battery terminal such that it can be easily attached and unattached like alligator clip ends. Attach a digital multi meter (DMM) as shown. Attach the negative battery terminal to the DMM AMP INPUT. There are typically two AMP inputs on the meter and they are labeled "A" and "mA" (or mA uA). Use the input that is fused for at least 1 amp of current; typically this is the "A" input. Attach the battery negative post to GROUND (GND) or COMMON input of the DMM (Figure 1). Set the DMM mode dial to mA or A (depending on the meter used).
KOL Measurement:
With the jumper wire connected as shown in Figure 1, the meter will show an erroneous reading - ignore it. Wait 30 minutes (so that the vehicle goes to sleep). Then disconnect the jumper wire and read the meter. You may notice the meter reading periodically jumping up in value. That is normal and is the body security module (BSM) or vehicle security module (VSM) polling transmitters and possibly the tire pressure monitoring system (TPMS) transmitters. Use the lower value. If the meter has "average" reading capability, use it to read the average value. For example, a normal reading could be 0.019 A (19 mA) with a momentary periodic jump in the reading to 0.048 A. Use the 0.019 A reading. The 0.048 A reading is due to the BSM (or VSM) momentarily waking up to pole the remote keyless entry (RKE) or TPMS. If you set the DMM for average, you will get a more stable reading of about 0.019 A to 0.020 A.
The maximum average KOL current for a normal functioning vehicle in sleep mode will be no greater than 28 mA (read on the DMM as 0.028 A or 28 mA). A vehicle will be in sleep mode after 30 minutes of no electrical system activity. All KOL measurements are taken while the vehicle is in sleep mode. A KOL measurement of greater than 28 mA is considered a KOL fault/issue. When the vehicle is awake (not in sleep mode) the typical KOL for a normal functioning vehicle is 860 mA +/- 100 mA (read on a meter as 0.86 A or 860 mA).
NOTE
IF UNSURE ON HOW TO READ THE DMM CONSULT THE DMM OPERATING MANUAL.
If the vehicle has a KOL issue, expect KOL readings of greater than 0.029A (29 mA) and as high as 0.96A (960mA) after the vehicle is asleep. Perform KOL fault isolation to find the cause of the excess current draw.
Fault Isolation:
Fault isolation for a KOL issue is done by removing a portion of the electrical system and rechecking KOL to see if by removing that portion of the electrical system the KOL reads normal (less than 0.028A). Removal of a portion of the electrical system can be done three different ways:
1. Disconnect one module at a time.
2. Pull fuses out one at a time (this will remove both modules and circuits).
3. Disconnect harnesses at various interconnects (this will remove modules and complete sections of the vehicle harnesses).
To isolate a high KOL issue disconnect a portion of the electrical system, wait 30 minutes, then take a KOL reading. If the new reading is greater than 28 mA, then reconnect the disconnected portion and then disconnect a different portion of the electrical system, wait 30 minutes, then take a KOL reading. Continue this testing until the KOL drops to below 28 mA. The portion of the electrical system removed that causes the KOL drop to normal contains the issue.
Exception - The BSM (or VSM), Cluster, and PCM contain bus termination resisters and should NOT be disconnected from the harness for KOL testing. Isolate these three modules last using the order and method listed:
a. Isolate the PCM using fault isolation method (1) and recheck KOL
b. Isolate the VSM using fault isolation method (2) for fuses F5 and recheck KOL
c. If the high KOL is present after all other modules have been isolated, swap the cluster for a known good cluster and recheck KOL
The high KOL is still present after all modules have been fault isolated, isolate for pinched harness circuits using fault isolation method (3).
NOTE
IT IS RECOMMENDED THAT YOU RECONNECT MODULES, FUSES, OR A PORTION OF THE ELECTRICAL SYSTEM PRIOR TO DISCONNECTING ANOTHER.
Removing a portion of the electrical system will cause the KOL to drop slightly. But ONLY the removal of the portion of electrical system with the KOL issue will cause the reading to drop to BELOW 0.028A (28 mA).
For example, a vehicle's KOL is measured to be 0.4A (400 mA). The dual climate control seat module (DCSM) is removed by disconnecting the module. KOL is again measured and found to be 0.34A (or 340 mA). The DCSM is reconnected. Next the power liftgate module (PLGM) is removed by disconnecting the module. KOL is again measured and found to be 0.022A (or 22 mA). The PLGM is the root cause of the issue because the KOL fell below 0.028A (28 mA) once removed. Removal of the DCSM did not cause the KOL to go below NORMAL.
If you use fault isolation method (2) or (3) you will need to further isolate the KOL on the portion of the disconnected electrical system. For example, if you pulled a particular fuse that fuses the radio, climate control head, and steering wheel switches and the KOL dropped to below normal, the problem could be any one of those components on that fuse or the fused circuit. To further isolate, the fuse would be plugged back in and the individual components pulled separately with KOL checked for each component pulled.
ISOLATION HINTS:
If the KOL is greater than 0.6A (600 mA), use fault isolation method (1) starting with the DCSM.
If the KOL is greater than 0.9A (900 mA), use fault isolation method (3). This is probably a short circuit.
WARRANTY STATUS: Information Only
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