93 Dodge Intrepid, code 66

Hello,

I posted here awhile back about my problem with my '93 Intrepid. It
will randomly drop into second gear and the speedometer drops to 0.
It stays this way anywhere from less than a second to around thirty
seconds then goes back to normal. The output speed sensor has been
replaced my mechanic has gone over everything he can think of. The
odd thing is that, up until now, it has never produced any error
codes.

After a trip home where it did this 6-8 times, I tried the key trick
just for the heck of it. It got 12 66 55. So I took it to the
mechanic today so he could check it out with his code reader. The
reader said there were no error codes. We tried the key trick and 66
was still there. He was able to look up 66 but is not sure exactly
what circumstances would produce this code.

BTW, does anyone have a definitive answer to how long it takes for
the code 12 to clear and what specifically triggers it? I think I
might have an interruption of power somewhere and the code 12 might
also be a clue.

Thanks for any help,
DSF

 

The diagnostics in the FSM always tell you: verify that the problem isn't
one with the connection to the sensor before replacing it. In this case, so
many of these sensors fail that it's reasonable to shotgun it and just
replace it first. But now that you still have the same symptoms, it's time
for someone to start taking a real good look at the wire and connector that
go to that sensor. Bet the problem is in there.

--Geoff

 

Code 66 means that the body computer or transmission computer has
not communicated with the engine computer for at least 10 seconds
via the CCD bus.
causes for this include;
an open in the CCD + circuit
an open in the CCD - circuit
a failed PCM
no power to the transmission control module
a failed transmission control module

 

I appreciate the response, but the first paragraph of my message was
meant to bring anyone replying up to date. The speed sensor was
replaced months ago. Since then pretty much everything involving the
sensor and it's connections has been gone over.

Thanks,
DSF

 

Thank you for the info. The part about the 10 second interruption is
very interesting. Although I said above that the effect can last
anywhere from less than a second to around thirty, I'm beginning to
think that most times it's shorter than it seems to be. (When you're
driving at highway speeds and it drops to second gear, it can seem
like a lot longer time!) I believe one of the most recent occurrences
passed the 10 second mark, which is why there have been no error codes
previously.

I think the best possibility might lie with the last two reasons you
listed. I like the "no power..." reason better since it's probably
the cheapest. Let me toss a scenario out there and see if there are
any faults with it.
The TCM loses power. Since the TCM drives the solenoids in the
xmission, any that are on turn off. I would assume that leaves the
xmission in 2nd gear. It would make sense to design it this way: no
power=limp mode. The output speed sensor feeds the TCM. Since the
TCM is dead, no forwarded signal for the speedometer, etc.
Power returns < 10 seconds: Everything returns to normal.
Power returns > 10 seconds: The PCM reports error 66.

How does that sound?

DSF

 

#66 no ccd buss message from the bcm
the bcm is on the right side of the dash and requires removing the lower
dash and console to get to it

 

Sounds like time to pull the PCM and TCM connectors and do some
cleaning.... as well as double-check all the ground strap connections.

 

[snip]

You've got it.

 

Thanks for the comfirmation. Any idea which pin(s) (or wire
color(s)) on the TCM connector is used for power?

DSF

 

Thanks. That's one of the first things I did. No help.

DSF