DodgeIntrepid.Net Forums banner

Tranny help. Code 1698.

8K views 62 replies 4 participants last post by  KevenP 
#1 ·
Hey all,
1999 LHS 90K miles.
Car has to be reved around 2K to move. Once moving, it has all gears.
All the lights on the dash where the P R N 1 2 3 4 all have squares around them.
CIL is on.
Sometimes it'll put itself in 'limp' mode.

New TCM and speed sensors. Fresh fluid.

Help! :)
 
#2 ·
P1698 (M)

No CCD/J1850 Message From TCM

No CCD/J1850 messages received from the electronic
transmission control module (EATX) or the Aisin
transmission controller.

Sounds like you have a bad TCM or a wiring issue related to the TCM.
 
#3 ·
Yep, you're right. Bad TCM.
I replaced it yesterday and had even more problems.
Replaced both speed sensors this morning, no help.
Just for giggles, I re-installed the original TCM and everything works. :doh:

So, I did have two bad sensors and bought a bad TCM.

Thanks!
 
#4 ·
The output of the range sensor is 4 contact closures showing the position of the shifter. If you know binary math, that would give 2^4, or 16, possible combinations of outputs, but only 6 different combinations (representing Park, Reverse, Neutral, Drive, 3, and 1) are valid and recognized by the TCM.

If there's a wiring problem on the range sensor (let's say, one broken wire), like Ron suggested, then invalid codes will result. When the TCM sees an invalid code from the range sensor, it lights up all the shift indicator lights in the instrument cluster. That should result in limp mode. Not saying that this is definitely your problem, but that was my first thought on it.

Since you say it sometimes goes into limp mode, the problem is apparently intermittent.

Make sure the connector on the TCM and range sensor are fully seated.

EDIT: I got interrupted while posting and see that you posted again. Probably the connector to the TCM was not fully seated.
 
#7 ·
Are you still seeing this from your first post?

"All the lights on the dash where the P R N 1 2 3 4 all have squares around them."

If so then you should check what Bill was talking about in post #4.

The P1698 is still a comm loss. Power to the TCM, PCI Bus Comm into/out of the TCM and others.

PCI Bus is a Violet Wire with a Yellow Stripe in all cases.
 
#8 ·
No. The car was fine for about 2 weeks and then started the 'limp mode' stuff again.
All the gears are shown selected and the speedo quits working. Within a mile, it corrects
itself.
Thanks for the info on the PCI bus wire and the range sensor. I'll pass that on to the mechanic.
 
#10 ·
So, after 2 mechanics and a transmission shop, I found out you can not use another part number TCM. I has to be the same as the original. I installed another TCM with the same part number and the problem went away.
That's not totally true. What year did the TCM that didn't work come off of?
 
#11 ·
Did you get a TCM from a 1998 car or a 2001 perhaps? As Peva asks? There's no separate TCM in 2002-2004 cars.
 
#12 ·
It's back, but different.
No codes. just puts itself in limp mode for 10-30 seconds and then fixes itself. :ahh:
Miles driven or temp make no difference.

Since my last post I've replaced the battery, TCM with correct part number from a '99 3.5.
and tried a jumper wire from the TCM to the ECU.

I'm thinking about replacing the complete under hood wiring harness.

Thoughts?
 
#13 ·
There are several possibilities, and we probably won't hit them all, and the probability of any one of them being *your* problem is about 5%.

Is it a pump pressure problem that is causing the delay in proper pressure? Does the filter need replacing? There is a very commonly used transmission filter on many Chryslers that is almost identical to our filter. It isn't an exact fit into the recess cavity in the transmission, but it's so close, you can push it in without much trouble, but the nipple that points upward and plugs into the pump inlet is a bit shorter than the nipple on ours, so the pump sucks air. The parts guys are so used to selling the other filter that they can get in the habit of selling them to everyone without looking it up. When I got my first Concorde, someone on a Chrysler newsgroup warned people of the wrong-filter problem, and I kind of forgot about it. Darn if a few months later I did a transmission fluid and filter change and turns out the mail order dealer that I bought the filter from shipped that other filter. I only noticed it because it didn't fit perfectly into the cavity, then I remembered what the newsgroup guy posted, so I pulled it out and compared it to the old filter, and the nipple was noticeably shorter. Just glad I noticed and remembered before putting the pan back on and refilling.

That's just an example of what I'm talking about with several possibilities, but the chance of any one of them being *your* problem is pretty small. But do think about if your filter might be slightly clogged or having been replaced with the wrong one.

Then there are the wiring and range sensor possibilities already mentioned, except it seems that your problem repeats itself at each startup and goes away.

Back to the TCM being the same part number or not, I can tell you that my '98 TCM went bad, and after researching it, I bought a used 2000 one, only paying attention to which engine it had been used with because the gearing is different for the 2.7 vs. 3.2/3.5. Worked flawlessly, and still is. You can't expect the mechanics to know every line of car and all their quirks and variations like DIY'ers who own a particular car for years and hang out on forums for years like us (IOW, a pretty sad bunch of people). :) But the mechanics pretty much have to tell you to use the same part to be on the safe side (same with the salvage yard interchange lists - they paly it safe and often don't list an interchange when the parts are in fact interchangeable).
 
#17 ·
Could be another module on the bus dropping out and taking the rest of the bus with it. Or wiring still.
 
#19 ·
Something is happening to the communications across the PCI Bus. With the DRB tool "Blanking out" that confirms the PCI Bus went down.
 
#20 ·
Maybe you've been replacing the wrong module? See below.

Symptom:
P1698-NO BUS MESSAGE FROM TRANS CONTROL MODULE

When Monitored and Set Condition:
P1698-NO BUS MESSAGE FROM TRANS CONTROL MODULE
When Monitored: Equipped with automatic transmission, the ignition key on, engine
running, transmission in drive, vehicle road speed and battery voltage greater than 10
volts.
Set Condition: No bus messages from the TCM for 10 seconds, two trips required.

POSSIBLE CAUSES
FUSED B(+) CIRCUIT LESS THAN 10.0 VOLTS
FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
PCM GROUND CIRCUIT(S) OPEN
PCM INTERNAL PCI BUS OPEN
PCM PCI BUS CIRCUIT OPEN
WIRING HARNESS INTERMITTENT DEFECT
 
#21 ·
At first I thought it was a mistake in the references to the PCM for the problem of TCM communications but I went and looked at the other codes for different modules losing communication and they reference the PCM as a cause also.

The Data Link Connector...where the DRB connects under the dash communicates with the PCM. So it appears it's possible the PCM is crapping out momentarily and bringing down the PCI Bus. Remember when you lose Comm to the TCM the transmission goes into Limp Mode. It doesn't have to be an internal transmission fault to cause this.
 
#22 ·
Have you removed the connectors to the PCM and verified they're clean inside with no corrosion or damaged pins?
 
#23 ·
Could also be the ignition switch as shown in possible causes above. And you should check the grounds on the PCM also.
 
#25 ·
OK. Same problem exists. Replaced the solenoid pack in the tranny and the ignition module.

I'm no good at reading the schematics in my FSM. Where physically are the connections and/or grounds I should be looking at?

I'm running out of enthusiasm for fixing this thing.
 
#26 ·
What's the "Ignition Module"? Do you mean the PCM?

The connections/grounds I was referring to are at the PCM and TCM up near the front bumper on the drivers side.

Why did you replace the Solenoid Pack?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top