98 chrysler concorde lxi all gauges and a/c die after 15 min of driving

98 chrysler concorde lxi all gauges and a/c die after 15 min of driving
the only way to get working is to unplug battery for 10 to 15 minutes
and everything works again for another 15 minutes or so help please

 

The two main possibilities:
(1) Your battery is dieing. This is typical behavior in the LH cars
when that is happening.
(2) Something is killing the communications bus (called the 'PCI' bus)
that allows all the electronics in the car to communicate to each other.

When the problem occurs, if you also get a message flashed on the
odometer "NO BUS", then it is (2). If no such message, then have your
battery tested. If the battery is more than 3 or 4 years old, then
you're over-due anyway, and might as well replace it. Even if that is
not the problem (it probably is), it should be replaced pre-emptively.
If that fixes it, then keep on trucking. If not, then post back. Post
back anyway.

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

 

Another possibility is a flaky ground for the Body Controller computer,
causing it to lock up. The first-gen LH cars were more notorious for
that than the second-gens, but I'd assume that the same thing still
happens if that ground connection gets flaky. A look at an LH car wiring
diagram should tell you where all the grounds (there are many!) are
located. On the first-gen, the BCM ground is behind the center console
kick-panel just to the right of the accelerator pedal, but I'm not sure
where it is on a second-gen.

 

Same on 2nd gen. That's a pretty solid ground they have - but it's
always possible someone loosened it.

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

 

new symptom to problem the odometer now when everything shuts down says
"no bus"

 

OK - the bus goes between all the various modules of the car - TCM, BCM,
PDM, Instrument Cluster, Air Bag Controller, ABS Controller, ATC
controller, etc., etc. etc.

The bus originates and is controled by the BCM. One of three things is
happening:
(1) The BCM is bad.
(2) A bad connection in the wiring either interrupting the bus coming
from the BCM or shorting the bus out.
(3) One of the other modules is internally shorting the bus out (which
kills it for everything).

Of the two real world cases I have read about or seen on this problem,
*BOTH* turned out to be a bad TCM. The case I read about was on the
300M Club. My own personal case actually worked out well for me - a
local used car dealer had a '98 Concorde LXi that had this problem
(intermittent), and spent all kinds of money at the dealer getting it
"diagnosed", replaced the BCM, all without success. They kept it for
over a year hopipng to fix it and sell it, but they couldn't (couldn't
pass inspection with Air Bag light on the dash, speedometer crapping
out, etc.). I had bought my '99 from them, and they knew I liked
Concordes, so they offered it to me for $1k to get it off their lot. I
took a chance and got it, and by correctly troubleshooting the problem,
pinned it down to a bad TCM. Got a TCM out of a junk yard for $20.
Problem solved.

Now - since it theoretically could be many many things killing the bus,
this is a risk for you to take my advice here, but because the cost is
less than $50 for a used TCM vs. hundreds of doallars having someone
troubelshoot it (with no guarantee of them coming up with a proper
diagnosis and repair), I would highly recommend doing the following.

You can use any TCM out of any 2nd gen LH car (300M, Concorde, LHS,
Intrepid) from '99 thru '01. If you get one from a '98, it must be from
a vehicle without autostick (in '99 the TCM was designed to detect
whether autostick or not and work accordingly; in '98, the TCM was hard
programed for either autostick or non-autostick - so one from a '98 that
is hard-programed for auto-stick will not work in your Concorde without
auto-stick).

I would avoid a TCM from a '99 since the firmware was poor (bad
shifting) and it would cost you $60 to $120 to have a dealer reflash it
with later good firmware. So, I would recommend one from any '00 or '01
LH car. It will be plug-n-play. Also the later ones are probably more
reliable and would have the latest firmware for good shifting.

The interchangeability from year to year (with the caveat about
autostick for '98) has been confirmed by myself and by some independent
experiments done by one of the members of the 300M Club. My '98 is
running great with a TCM out of a '2000.

To locate one from a junk yard in the same part of the U.S. as you with
a TCM for sale, go to www.car-part.com and drill down for '00 or '01
Concorde - then select "Transmission Computer" for the part, then
"Transmission" on the selection box that comes up. You will notice that
the list that comes up contains all LH cars - it knows that they are
interchangeable between the badges.

However, it does not know that they are (within the guidelines I
mentioned) interchangeable between years, so you would have to do a
separate search for, say '01.

Now - notice at the bottom of the page that one of the page numbers has
an asterisk beside it. That is the page of listings where they
transition from lowest listing price to listings with no price
specified. You want to go to that page and work backwards from there to
find a good yard with a lower price. Your lowest price will be below
$30 instead of the several hundreds on the very first page of listings.

*********ONE MORE VERY IMPORTANT POINT I ALMOST FORGOT*********:

There is a difference in TCM firmware that will affect
speedometer/odometer reading. Their are two different drive train gear
ratios that came on the LH cars. That affects your speedometer/odometer
reading, and has to be compensated for in the firmware in the TCM. The
www.car-part.com listings don't reconginze that fact, so, if you weren't
aware of that fact, you could end up with one for the wrong gearing.

Here's how to tell: If the vehicle came with a 2.7L engine *OR* if it
was a 300M **SPECIAL** *OR* if it was a Dodge Intrepid **RT**, it will
have the higher (non-standard) gearing. Your Concorde being an LXi
would have the 3.2L engine and the standard gearing. So when you call
the yard, ask them about the vehicle it came out of - if it came out of
any that I mentioned at the beginning of this paragraph (any 2.7L, 300M
Special, Intrepid RT), tell them to look at another one - keep going
until you hit one that is not one of those. Chances are you'll hit it
the first time, but you have to check.

If they argue with you about year or gearing, then tell them you can't
go by the listings - that you have better info. If they argue with you
(like the guy I got on the phone), then hang up and try another yard.
The yard I got mine from refused to warranty it because it was for a
different year car - he insisted on going with the listings. The guy
also was an a-hole and wouldn't tell me anything about the vehicle it
was coming out of as far as engine size (for gearing) - so I took a
gamble and got it anyway because the $20 price was worth taking the risk
- it turned out to be the right gearing, and it was a good unit. No big
deal if it hadn't worked or been the right one - I just would have been
out $20 and simply ordered one I knew was the right one from a better
yard for a little more money.

Post back with questions or results. Like I said - I can't guarantee
that the TCM is the problem, but I'm betting it is, and I doubt you'll
be able to get it properly diagnosed, and you'll end up paying hundreds
of dollars whether it gets diagnosed and fixed or not.

If you're not wiling to take the risk, I'll give you $1000 for the car
as is.

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

 

i ordered a tcm from ebay do you know what year bcm are compatible with
my 98 concourde lxi

 

What!! You didn't read all 3542 words of my reply!!

The answer to that was in there, but it all boils down to the following:
(1) *Any* year LH car TCM '98 thru '01 will work, except, if it's from a
'98, it must specifically be out of an LH car without autostick (if from
a Concorde or LHS, you're safe, as they weren't available with
autostick; and 300M's didn't come out until '99).
(2) If you didn't check or specify, you have a 50/50 chance of the gear
ratio being right or wrong. If the one you get is from an LH car with a
2.7L engine, or from a 300M special, or from an Intrepid RT (or from one
that was replaced because someone mod'ed it with the higher gear ratio -
a popular mod), your speedo and odo will be off (it will read high) by
6.3%. If you end up with the wrong one, you could, for under $100, opt
to mod the gear ratio which would correct the speedo/odo, give you
quicker accelleration, and slightly worse fuel mileage.
(3) It would be best to avoid the '99 TCM since the firmware was not the
best (for smooth shifts) unless someone had it re-flashed with the
upgraded firmware (per a TSB). It would cost you $60 to $120 to pay a
dealer to re-flash a '99 TCM with the later firmware.

That's it in a nutshell.

Regarding (2), above, if your problem is intermittent, before you
install the replacement, while things are working, pick out some
mileposts 5 or more miles apart and check the trip odometer reading
change between them - then compare after the swap and see if it's the
same or around 6% different. Or after the fact, compare to the
suspected accurate odometer of another vehicle over the same 5 or 10
mile drive.

If you don't know what year it came out of, after you get it, post with
the part number on the bar code label, and I will tell you what year TCM
you got (part number changed every year even though they are for the
most part interchangeable outside of the previously stated caveats).
Unfortunately, for any given year, the part number is the same
regardless of which gear ratio the firmware is for.

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