98 Intrepid ES - Bad BCM??

Car has been great, nothing but maintenance items to date. 85K miles. 3.2
eng, autostick tranny, a typical ES model. A few days ago, the wife was
driving to work, and lost the speedo, tach and a/c. Car continued to run, so
she continued to work. Drove home, these items came on and off
intermittently. I've done some digging since then on google, read about a
'lot' of cars going into limp mode. Ours did not do this, we had all four
gears, was able to confirm by using autostick. A *very* few shifts were
abrupt, and moving from a stop while going uphill occasionally caused sudden
starts, but nothing unsafe or particularly bad about the tranny. Just
different behavior.

Took car to local independent shop, but they did not have all the Mopar
scanning computers to do thorough diagnosis. They found several codes, but
could not pinpoint the problem. They strongly suspected a bad BCM (body
control module), but left open the possibility of a communication issue
somewhere on the car's bus serving all modules. They told me this meant it
could be another module (or more) causing the problem, so they felt better
not throwing parts at it. Suggested taking it to dealer for better analysis,
which I did.

Dealer did their thing, determined the problem to be in the BCM, and
attempted to reprogram it. My impression, based on how they relayed this
story to me, was they were a bit surprised to find that just doing this
solved the problem. Maybe this is normal and I misinterpreted...They did
their test drive and put it back on the scanner, and found everything to be
normal. Two hours shop time, no parts. I drove it home last night, made a
few stops, about 25 miles total, everything was normal.

This morning, the problem has come back, with new wrinkles. Went out to
start it, it runs for a second or two, then shuts off. Does this four/five
times in a row. Go inside for a while to deal with unruly children (the wife
is at work now, took my car), came back in about an hour. Try starting, it
won't fire at all now. All dash lights come on, but no start. On a whim, I
put car in neutral, and it starts right up. Not only that, but it stays
running. The same problems with no speedo, tach or a/c have come back, but
at least I now have a car that runs.

Now at the end of this long story - do I proceed to have the BCM replaced?
The obvious answer seems to be yes, but just want to see what others think.
Here are the codes from my local shop's diagnosis. Did not get them from the
dealer:

P1685 - SKIM invald key
P1687 - no MIC bus message
P1695 - no body CCD messages
P1698 - no CCD messages from TCM

I'm starting to suspect a tranny or TCM problem, maybe instead of or in
addition to the BCM. I'm basing this on the infrequent, irregular shifts
noted above, the fact that I got the car to start today when I put it in
neutral, and the last code shown above. I'm definitely not a Mopar tech or
shadetree mechanic, this is just my guess. Another wild thought: could a bad
battery be causing any of these problems? I have never replaced it. We
bought the car used three years ago, so it's probably the original. Haven't
pulled the wheel off to get at it yet. I did read some other threads where
the battery was the culprit of some major problems related to control
modules. I'm assuming that after all these scans a weak or bad battery would
have shown up, but I really don't want to assume anything at this point.

Thanks,

Joe

 

Yes a bad battery can cause all kinds of problems with electronics and
I was thinking after your description that this was the problem. You should
also check all your grounding points for loose connections.

If it's an original battery from 1998 it's 5 years old now and frankly it's
amazing
it's still running.

Ted

 

I had similar intermittent problems on my '99 Concorde when one of the
connections at the postive jump node became just loose enough to present
a high resistance connection between the batery and the power system.
(Be aware that power from the battery to **every** system in the car
except the alternator passes thru that jump node.)

The connection gradually degraded from the heat and started arcing over
intermittently. My first symptoms were flickering headlights and
dashlights when driving at night, then as it got worse, more problems as
you describe, including, eventually, intermittent starter operation. If
I had not noticed the smoky looking metal on and around the jump node
stud, nut, and one of the cable terminals at the node, it couild have
taken me a long time to find the root cause because the nut actually
felt tight. The heat and constant arcing between the stud and nut
galled the threads just enough to make it act like it was tight (as far
as clamping force on the terminal) when it really wasn't. A little
extra torque on the nut overcame the resistance to turning, and it
tightened up on the terminal - problem solved, never to return.

And I agree with Ted - this also could be a battery going south.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

Hi Joe, don't worry about stupid questions, we've all been there. Removing the
air filter box is actually really simple. The only tool you need is a
screwdriver or socket to loosen the hose clamp.


1.) If so equipped, move the cold weather group (battery and block heater) AC
power cord out of the way. However, you probably don't have this unless it was
ordered with that option of the car is Canadian.
2.) With a screwdriver, loosen the hose clamp that connects the air hose to the
air filter box. No need to remove the clamp.
3.) Remove the hose from the filter box. Remove filter box lid. Might as
well inspect the air filter too.
4.) The filter box is attached by rubber receivers. Grab the driver side
(left) of the filter box and lift straight up. Then pull the filter box toward
the driver side (left).
5.) While you have the box out, it is a good time to clean out all the crap
that collects in the bottom.
6.) Once the box is out, you can now (partially) access the battery. Undo the
battery tiedowns, disconnect the terminals, and the battery moves aft, partially
into the wheel well. Then the battery comes straight up. No need to remove
the wheel.

 

Here is the official service manual procedure: (The more recent LH manuals provide
much better documentation for this than the 1998 or 1999 manuals).

BATTERY REMOVAL
The battery is accessible without removing the right front wheel and tire assembly..

(1) Verify that the ignition switch and all accessories are OFF.
(2) Turn the steering wheel to the full right position.
(3) Disconnect and isolate the negative battery cable remote terminal from the
remote battery post.

WARNING: NEVER GET UNDER A LIFTED VEHICLE IF NOT SUPPORTED PROPERLY ON SAFETY
STANDS.

(4) Remove the air cleaner housing. Refer to the index for the location of the
procedure.
*Greg Note: See below*
(5) Remove battery splash shield. Refer to the Body section of the service manual
for the procedure.
(6) Disconnect the heater blanket cord, if equipped.
(7) Remove the two short bolts from the battery hold down and remove the hold down.
(8) Disconnect the positive battery cable from the battery.
(9) Slide the battery toward rear of vehicle.
(10) Disconnect the negative battery cable from the battery.
(11) Remove battery from vehicle.

INSTALLATION
(1) Position the battery in the battery tray.

(2) Connect the positive and negative battery cables. Torque to 16 N·m (150 in.
lbs.).
(3) Connect the heater blanket cord, if equipped.
(4) Install the battery hold down and install the hold down bolt. Torque to 16 N·m
(150 in. lbs.).
(5) Install battery splash shield. Refer to the Body section for the procedure.
(6) Install the air cleaner housing.
(7) Connect the negative battery cable.

 

LOL! I never thought of that. I can see it now: Bill and Ted - the
jaded duo!".

Take a look at the photos in this thread on
www.dodgeintrepid.net:http://www.do....php?s=&threadid=15904&highlight=Optima+blood

Along with Greg's description, they may help, but yeah - the key is
getting the air filter box out.

If you can spend $100+ on a battery, you might consider an Optima red
top - it's a solid electrolyte lead-acid battery. It is claimed that
they should hold up for ten years (I have no scientific studies to prove
that). I didn't want to deal with the battery on this car again.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

Thank you everybody for the tips and to Bill for the link. I'm going to go
for the Optima - plan on keeping this car for a while.

Regards,

Joe

 

You're welcome.

You should be able to find the Optima for something like $99 + maybe $20
shipping on the net. My local Advance Auto Parts wanted $169 + tax for
the exact same battery which was out of the question.

Make sure you get the Optima Model No. 34/800S (P/N 8002-002). I say
that because there are three 12V models of the red top, and that's the
one you need (top terminals only). The other two have dual terminals
that may not fit in the space, and one is lower capacity. Some
suppliers play games by making up their own internal part numbers to
make you think it is a larger capacity one (by building in the CA rating
rather than the CCA rating like Optima does) so you will go with them
rather than a competitor selling the exact same Optima battery (Advance
tried to pull that one too). If they assure you that they are using the
Optima part number, you should be safe.

Start with batteryweb.com (http://optimabattery.com/optima.cfm takes you
right to their Optima page). They are out of Florida, but have
distribution centers all over the U.S. so the shipping costs stay
reasonable and shipping times are typically 1 day with ground shipping.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

before you do anything replace the battery and throughly clean the connections
at the battery and were the posts are on the strut tower
from the codes i see i would suspect a bad connection verses a bad bcm

 

Just finished installing the new Optima. Checked around locally (SW Ohio),
and found Advance Auto had it on sale for $119 plus tax. Ended up at $128.
The few bucks difference was worth it to me for having a live person to deal
with and to where I could bring my old battery. The link to that place in FL
was good, and I would have gone there if Advance was selling at their
regular $180 price!!

Only two surprises, one very minor and one a bit bigger. Minor problem:
Optima battery case was slightly shorter than than the OEM battery (yes, it
WAS the original battery, as I suspected). Just put a couple wooden door
shims between strap and case, all is well there. Bigger problem: positive
terminal screw was nearly welded to the nut. Liberal use of baking soda and
water got rid of the crud, lots of torque snapped off the bolt, freeing up
the cable. Cleaned everything up, replaced bolt/nut, and put everything back
together. I did remove the RF wheel - made life much easier when dealing
with that bolt/nut. Negative terminal and all hardware there was spotless.
Checked the remote pos and neg blocks, everything was good and tight there,
no corrosion or loose hardware.

Car is running again, with the same problem as before, but at least we can
rule out the battery as the problem. When this thing goes back to the
dealer, I'm expecting them to want to replace the BCM. Do these even
*occasionally* lose the ability to retain their programming, and thus have
to be replaced? I'm wondering if, now that a good battery is in the car, a
second attempt to reprogram the BCM is worthwhile? I think if I make them
understand that a routine check of the battery would have been a good idea,
I can get them to do the reprogram gratis. Can't hurt to ask...

Thanks for all the help everyone offered. Even if the battery ends up not
being the cause, it was well overdue to be swapped out, so I consider the
exercise a very worthwhile one. Just wish I would have done that first.

Thanks again,

Joe

 

Sounds like a reasonable decision.

Funny - when I put my Optima in, it turned out that the battery was not
my problem either, but, like you, my battery was on borrowed time too.
My problem turned out to be a poor (intermitent) connection at the
positive jump node - check that out on yours - it just might be your
problem too.

Yes - the thing you noticed about the battery being shorter was
something I addressed in that thread on the dodgeintrepid.net forum that
I posted earlier in this thread
(www.dodgeintrepid.net:http://www.do....php?s=&threadid=15904&highlight=Optima+blood)
- I was Peva there.

In the thread, I explain how I solved that concern (the battery
terminals being closer together and thus more likely to short to the
hold-down).

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

No. Pos and neg terminals at the battery and remote terminals were checked
and cleaned as needed. The only bad one was the pos at the battery. Did not
check the ground (or is there more than one?). I'll definitely check them if
anybody would be kind enough to give me location(s).

Dealer looked at car again today for at least 90 minutes, came back with a
definitive "bad PCM". That's the Powertrain Control Module. I have had some
rough shifts, but very infrequent. Had none prior to this problem, so it
makes sense. They are saying that this module is causing communications
problems on the bus shared by all other modules. This made it difficult to
diagnose, and was causing the BCM to throw codes.

Here's the fun part: quoting $800 for parts labor!! They "consoled" me by
saying that "they don't see these very often". Wow, lucky me...

Appreciate all the help, and will look at the ground situation.

Thanks,

Joe

 

Sounds like you've done your due diligence in eliminating the
simpler/cheaper possible causes first. If it isn't a ground issue like
Art suggested, then it sounds like the dealer is right - after having
eliminated the other causes, it sounds like anything other than
replacing the BCM will be an excercise in denial of reality which will
only waste time and money.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")