'02 300M: Code P0700 and...

1. Check Engine light on again. At first I assumed it was P0441 again,
but I checked and found it was P0700, which I understand is a somewhat
general "Automatic Transmission Fault" message. Pulled the fuses for the
computer and left them out for a while, and the vehicle ran for a couple
of miles before the CEL came on again and the transmission shifted down.
"Argh! Limp mode!" I thought, but I found that it *will* shift up from
2nd but only at a higher-than-normal speed.

2. The Climate Control display is blank. The fuses all seem to be OK.
All the CC controls seem to work OK, but there is no display.

Is there any one fault that could account for *both* these problems?

The transmission problem seems most likely to be a sensor failure, from
what I have read, but where do I look for the cause of the blank CC display?

Perce

 

The Climate Control display has come back to life. I'm going to check
the transmission fluid level with the fluid warm. Cold and engine off
it's fine.

Perce

 

No, you have two seperate problems.

The P0700 code indicates a problem with the trans. You will need a scan tool
capable of communicating with the trans computer to determine what the exact
trans failure code is. A common failure seems to be the input and/or output
speed sensor failure. Don't just throw parts at it, have it scanned so you can
find out exactly what the problem is.

 

Trans fluid level is not monitored by the trans computer and will not set a
code.

 

The CC display is blank again.

I was thinking that low fluid level might cause give rise to a shift
problem that might in turn generate the P0700 code. But the level is
fine hot and with the engine running.

Perce

 

Further Googling suggested a faulty input sensor (in stock at all the
local Advance Auto stores for $16.xx), but with car on ramps I can't
reach the sensor anyway -- somewhat limited wrist mobility. On a hoist
no problem, I'm sure.

I assume there's no reason to go to Chrysler dealer rather than to
friendly neighborhood NAPA-affiliated repair guy? Or would only Chrysler
dealer have the *right* scan tool?

Perce

 

You may be able to reach it from the top.

You would have to ask the shop if the have a capable scan tool. The
Chrysler dealership would definately have the proper scan tool.

 

Friendly neighborhood NAPA-affiliated repair guy recommended taking it
to the Chrysler dealer or to a transmission specialist, so I took it to
the dealer that's been servicing it for the last 4+ years. Took a while,
but they eventually got additional codes (I didn't write them down) that
corresponded to those in a TSB concerning some valve(s) or other. They
have to order in parts (due tomorrow morning) and replace the valve body
and other parts. The extended warranty (which I thought had expired
already) will cover it for the standard $100 deductible vs. $600+ for
parts and $200+ for labor.

Perce

 

Glad to hear you got it fixed so quickly. Nice to have it covered under the
extended warraty!

 

I am even more glad today that it's being covered under the extended
warranty, because now they have discovered that yet other parts need to
be replaced -- something about contamination of some seals.

Perce

 

The ATC display intermittently going blank is a very common problem on
the LH cars. I would think that woujld be covered under the extended
warrranty too - hopefully it will decide to act up when they're looking
at it - perhaps a gentle banging with the fist (on the ATC head unit)
will cause it to act up. Or perhaps pushing on the display with your
thumb will turn the problem on and off - often it will.

If you want to take care of it yourself:
Solder cracks on surface mount parts on the p.c. board are the problem.
Some (myself included) have been successful at resoldering the loose
parts, but you can buy the entire ATC head unit all day long for under
$50 including shipping from junk yards. Plus, if you don't have the
tools or skills to do very delicate soldering, you'll ruin it anyway.

To find for under $50 including shipping, drill down at www.car-part.com
- narrow the geographical area as much or as little as you want.

Don't let the price on the first page scare you - they're listed in
order of descending price. Go to the page with the asterisk by the page
number at the bottom of the first page once you've done the drill down.
That will take you to the dividing line between the lowest price and
the "call for price" pages. Then work your way up the list for a low
price. When you put the vehicle description in, any that come up (of
other years and badging) will be interchangeable with yours - generally,
the newer the better.

Then pick a salvage yard in your region and call the 800 number - they
will ship to you for a nominal shipping fee.

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

 

<snip>

I am not averse to soldering, but how do I remove the display unit to
work on it?

Perce

 

You pull the woodgrained radio bezel rearward from the dash. Start out
by removing the ashtray (press down on the tab inside the ashtray) and
de-mating the cigarette lighter socket and traction control (if it has
it) switch connectors. Then pull the bezel away from the dash at the
bottom and work your way up to the top. The ATC control unit is
attached to the bezel from the front (non-visible) side with screws.
The connector has a tab on one side that you push in to release and
de-mate the connector from the control unit. There are some screws to
disassemble it - you will see a small fan built into the unit too.

I will warn you that the metal ends of the surface mount components, as
well as the p.c. board traces they attach to are fragile - they don't
stand up well to excess heat or mechanical stress.

On mine, the bad joints were on those blue resistors in this photo:
http://images14.fotki.com/v336/photos/4/42816/3749556/IMG_0834b-vi.jpg

Also - you may not even be able to see the cracks in the solder. The
only way I knew where they were was connecting the p.c. board back up to
the car out of the case and pressing different places until I found the
place that I could press on to turn the problem (the display lighting)
on and off.

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