Battery Re-Connect Procedure *

**DMAG** · 03-26-2005, 05:49 PM

From the service manual

BATTERY RECONNECTION
Note: This reconnection procedure is to be performed anytime the battery has been disconnected.
1. Connect the battery negative cable (2) to the battery
post and tighten the clamp nut.
2. Install the rear compartment floor trim panel.

CAUTION: Once the battery has been connected,
review and perform the following information as
applicable.

AUTO UP FRONT WINDOW
If the vehicle is equipped with the auto-up front window feature, once the battery is reconnected the door module
needs to be calibrated. The door module requires calibration anytime the battery or door module has been disconnected
for any length of time. To calibrate, perform the following:
1. Connect the battery cables.
2. Using the window switch, raise the window to the full UP position. Hold the switch in position for 1 second, then
drive the window all the way down to the bottom.

ELECTRONIC STABILITY PROGRAM (ESP)
If the vehicle is equipped with ESP, once the battery is reconnected, the Steering Angle Sensor (SAS) needs to be
calibrated. The SAS requires calibration anytime the battery or an ABS (ESP) component has been disconnected for
any length of time. To calibrate, perform the following:
1. Start the engine.
2. Center the steering wheel.
3. Turn the steering wheel all the way to the left until the internal stop in the steering gear is met, then turn the
wheel all the way to the right until the opposite internal stop in the steering gear is met.
4. Center the steering wheel.
5. Stop the engine.

**frank29** · 08-13-2005, 09:45 AM

I think M.D.S. reset is required in some cases. I have previously disconnected the battery with no M.D.S. ramifications; however, after a recent disconnect, my M.D.S. was inoperative. It seems to be a hit or miss thing. I am not positive the problem was related to the battery disconnect; I am positive M.D.S. wasn't working.

I hardly ever reset my average milage display. Normally, it hovers around 18. Recently, it dropped to 14. No change in driving habits. I reset my MPG reading and only got 17 mpg over a 30 mile trip using cruise control set at 60 miles per hour (it should have been 24 or so). I followed the MDS reset procedure and, PRESTO, my average m.p.g. jumped up to its historical levels.

My 05 300C owner's manual & service manual make no mention of this; however, the 06 owner's manual does. The second edition of the 05 Grand Cherokee does mention it. It seems strange M.D.S. reset would be required on some of these extremely similar powertrains and not on others.

If your mileage recently dropped with no change in driving habits, try the following procedure. No flaming required, I am not saying I bought this car with mileage in mind.....I am saying that when there is a drastic drop in mileage that a very simple reset solves, people need to be informed (especially since no documentation from Chrysler refers to the reset, at least for the 05 C models).

Procedure (as copied from another forum):

1. You need a fairly long, open, safe, straight road for a WOT run to about 35 mph.
2. Get engine up to operating temp., engine running and car stopped put selector in "D", move it to the right until in "1".
3. Turn off all electrical accessories (except lights if needed).
4. WOT run to 4500 RPM (about 35 mph), immediately remove foot from accelerator and do not depress the brake, let the vehicle coast with the throttle closed until the vehicle speed is again at 35 mph or lower.
5. Stop vehicle and place in "Park", verify all instrument cluster warning indicators are off.
6. Cycle ignition switch "Off" and back "On", but do not immediately start engine.
7. Hook up StarScan and clear DTC's
8. MDS calibration is now complete.

I stopped at step 6 due to not having a scan tool. There is one available for about $125 that I plan on purchasing for this and other reasons.

**fnkychkn** · 08-13-2005, 02:27 PM

no such thing as MDS recalibration. what you did is an adaptive numerator re-learn. this value only updates on decelleration because on decel there is no possible crankshaft speed fluctuation from misfires. this procedure is meant to allow the PCM to learn the difference in manufacturing tolerances and valve timing component wear. no need for WOT accell. this value will re-learn on it's own after the first few decellerations. it will not set DTC's.

**frank29** · 08-13-2005, 03:49 PM

Originally Posted by fnkychkn

no such thing as MDS recalibration

Hey, I admit there is confusion:
1) 2005 300C owner's manual doesn't mention it;2006 300C owner's manual does; other Chrysler products do mention it
2) TSB #08-013-04 dated 3-23-04 specifies a particular procedure to reset MDS
3) TSB #08-013-04A dated 4-6-04 replaces the original and all mention of MDS reset was removed

Originally Posted by fnkychkn

what you did is an adaptive numerator re-learn.

I can accept that. What is important to me is my two months of terrible mileage came to a screeching halt when I followed the procedure described in the second posting of this thread.

Originally Posted by fnkychkn

this value will re-learn on it's own after the first few decellerations

My car is a slow learner. 2,000 miles wouldn't do the job; the reset procedure did the job instantly.

If anyone with the 5.7 has noticed a deterioration in mileage with no change in driving type, try the procedure.

**fnkychkn** · 08-13-2005, 10:31 PM

Originally Posted by frank29

Hey, I admit there is confusion:
1) 2005 300C owner's manual doesn't mention it;2006 300C owner's manual does; other Chrysler products do mention it
2) TSB #08-013-04 dated 3-23-04 specifies a particular procedure to reset MDS
3) TSB #08-013-04A dated 4-6-04 replaces the original and all mention of MDS reset was removed.

my only source of TSBs is techconnect. when a TSB is revised, all previous versions are deleted. i thought i recalled that procedure, but when i looked for it, i could not find it. so i thought i just imagined it.

sorry for the wrong info. i just read TSB 08-013-04, the original version, from CoolVanilla's download site (thanks CV), and sure enough it says to recalibrate MDS. maybe they removed that part because too many techs were out there beating the crap out of customers cars :lol:

**BrilliantBlackHemi** · 09-18-2005, 07:10 PM

If you don't want to disconnect the battery and have the Sat Radio update stations and then have to perform these reconnect procedures, but you still want the computers to reset to factory for performance improvement, what fuse can you remove to accomplish this without the radio preset/station losses?

**Meister** · 09-20-2005, 06:57 PM

Originally Posted by BrilliantBlackHemi

If you don't want to disconnect the battery and have the Sat Radio update stations and then have to perform these reconnect procedures, but you still want the computers to reset to factory for performance improvement, what fuse can you remove to accomplish this without the radio preset/station losses?

GREAT question, BBH.

OK, who has the schematic?

**fnkychkn** · 09-20-2005, 07:55 PM

fuse 11 (15 amp) in IPM will remove B+ from PCM

**Meister** · 09-20-2005, 09:35 PM

Originally Posted by fnkychkn

fuse 11 (15 amp) in IPM will remove B+ from PCM

Bless you, oh mighty chicken.

I'm off to pull a fuse.

**RandomAccess** · 09-20-2005, 09:36 PM

Very cool... Thanks FC... Great thinking BBH...

Will pulling this fuse reset the trip meters and MPG etc...

**fnkychkn** · 09-20-2005, 10:10 PM

Originally Posted by RandomAccess

Will pulling this fuse reset the trip meters and MPG etc...

it shouldn't because that information is stored in CCN and/or EVIC

**BrilliantBlackHemi** · 09-20-2005, 10:36 PM

Ok, I see it now. Thanks. It's listed on 8W-30-5 and 8W-13-15 in the service manual and this is a fuse in the Integrated Power Module (under the hood). Also the illustrious fuse 17 is in the same unit removing power from the Anti-lock brake module (8W-35-2 and 8W-13-27)