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Dtc p1695

5K views 17 replies 4 participants last post by  DonB 
#1 ·
DTC P1695
DESCRIPTION OF DTC - No CCD/J1850 messages received from the body control module.

Near the beginning of anaborted short road trip this afternoon, I saw my gas gauge drop to empty and the low fuel warning light come on. I noticed when it was in this state, the EVIC display for ECO, AVG ECO and DTE were frozen as was the overhead trip odometer. I also noticed the speedo gauge odometer stuck and wouldn't count mileage. Then I noticed when both were set to trip miles, they would update erratically and differently. This happened the first time within the first mile.

When slowing to a stop, I'd hear a chime and all would come back online for a while but then go out again. Over the 20 mile duration of this trip, until I arrived back home, I didn't notice any other problems or errors. All other systems seemed fine and the car ran perfectly.

I didn't have time today to do anything but a key dance for the code and trade cars After returning this evening, a quick ride showed everything to be in perfect order and confirms the problem is intermittent.

Is this the behavior of a failing BCM or a loose connection/plug? Where do I start looking/testing to isolate the problem?

Current mileage 131810
 
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#2 ·
Probably wouldn't hurt to drop the knee bolster and take a peek for a loose connection. I'm too far removed from the LH lately to remember if the BCM has its own fuse or fuse link but, there are still lots of resources here to identify the B+ and Ground circuits. Just in case its something simple like that.
 
#3 ·
I pulled the fuse panel end cap just to have a look inside and give everything a jiggle test. I saw nothing odd at all about the part of the junction box. I didn't remove the knee blocker to be able to actually see anything yet.

I took it for another short ride this morning with no indication of trouble at all. So weird. It may be a dumb thing to do but I think I'll take it to town today (50 mile trip) and see what happens and try to gather more info. From the way it appeared yesterday, the worst that happens is I lose all mileage and fuel information until the fault resolves.
 
#4 ·
Hopefully you'll never see the problem again, but it wouldn't hurt to remove battery power (by disconnecting the top neg. jump post cable) for >15 minutes to reset the computers.
 
#6 ·
P1684 is very common even when everything is up to snuff. My theory is that they set the system voltage threshold for tripping that code a little too high - likely gets triggered when you start the car.

BTW - I searched the '02 ESM on 'CCD' and 'J1850'. CCD stands for Chrysler Collision Detection data bus system, and J1850 apparently is the SAE standard for automotive "Class B Multiplexing" - both are references to the Chrysler-specific PCI (Programmable Communications Interface) data bus system, which is what you more commonly see it referred to in the FSM and on this forum.

It's a single wire (i.e., single wire plus ground) going to all computers and other electronic modules (TCM, PCM, BCM, radio, instrument cluster, air bag module, ABS module, etc.) over which they all talk to each other. A short anywhere on that wire or in the interface with that wire in any one of the modules pulls the whole bus down, but that isn't necessarily the problem you're having. A bad connection would cause problems on a smaller scale (i.e., only certain functions). Or - yeah - the BCM just could have been malfunctioning (I get the feeling that it's more the "orchestra leader" of the whole bus).

At any time during the problem, did your odometer readout display 'NO bUS' instead of mileage numbers? It would display that if the instrument cluster doesn't see the bus for any reason. If that message didn't display, it would mean that at least part of the bus was functioning (i.e., no short anywhere pulling the whole bus down) and that the cluster was still connected (to the bus).
 
#7 ·
Thank you. I does seem like it "could" be a rather grim scenario for tracking this down with the fault being so intermittent. Once in a lifetime so far isn't very often.

No, I never saw that error message on the odometer. It would simply freeze in place and it (and the odometer in the EVIC) would sporadically update without an indication the whole system came back online. When it was shut down, I could switch the odometer between trip and total mode which seemed a little strange to me. I never saw any errors with any of the other instruments or lights. The only thing affected on the instrument panel was the fuel gauge and warning light and the odometer.

When I heard the chime and everything came back for a little while, all readings would instantly update and continue until the next cut off.

I reset everything today with the battery disconnect but only took a short ride afterward. I'll drive the longer ride to town tomorrow to see if it will goof up again.
 
#9 ·
This applies to 2002-2004 cars.

P1695-NO BODY BUS MESSAGES

When Monitored and Set Condition:
P1695-NO BODY BUS MESSAGES
When Monitored: Engine running. Battery voltage greater than 10.0 volts.
Set Condition: No BUS messages recieved from the BCM for 20 seconds.

POSSIBLE CAUSES
DTC RESET
COMMUNICATE WITH BCM
PCI BUS CIRCUIT OPEN
PCM

TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, erase DTCs.
Start the engine on and off several times. Leave the engine running for at least 20
second each time.
With the DRBIIIt, read DTC’s.
Does the DTC reset?
All
Yes ! Go To 2
No ! Refer to the INTERMITTENT CONDITION symptom in the
Driveability category.
Perform POWERTRAIN VERIFICATION TEST VER - 1.
2 Turn the ignition on.
With the DRBIIIt, attempt to communicate with the BCM.
Can communication be established with the BCM?
All
Yes ! Go To 3
No ! Refer to the Communication Category and perform the appropriate
symptom related to no communication with BCM.
Perform POWERTRAIN VERIFICATION TEST VER - 1.
279
DRIVEABILITY - NGC
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the PCM harness connector
Disconnect the BCM harness connector.
NOTE: Inspect the PCI Bus terminal at both the PCM connectors and the
BCM connectors. Check for corrosion, damage or terminal push out.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING
THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS
RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL
MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.
Measure the resistance of the PCI BUS circuit between the Special Tool #8815 and
the BCM harness connector.
Is the resistance below 5.0 ohms?
All
Yes ! Replace and program the Powertrain Control Module in accordance
with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1.
No ! Repair the PCI BUS circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 1.
 
#12 ·
Thank you RONBO. That kinda makes my head hurt and I don't have a DRBIIIt (maybe my brother has access to these tools) but is this a procedure that could identify the fault if it was not occurring at the moment?

The car behaved perfectly on the trip to town today. 48 miles and three stops of around 10 minutes each.
 
#13 ·
Update to situation.

After I reset the computers with battery disconnect, the DTC codes (other that the seemingly perpetual 1684) didn't come back even with the error sometimes present.

As long as I drove the car at least once a week, the car did well. No fuel gauge/warning light or associated errors. If I left it sit for longer, the problem would recur. I learned this problem would go away after 20 miles or so of driving or upon restarting after the first stop on a trip. I noticed when this fault was occurring, the instrument panel backlighting would turn on. I noticed the car doesn't seem to like high humidity and rainy days. This seemed to make the problem worse.

Then I left the car parked for 6 weeks. Things got much worse but I was able to learn some things.

Upon starting, it went nuts. Every light in the instrument panel came on, all ATC functions went out of control, in fact, nothing I checked worked properly. I got the 'NO bUS' on the odometer as well as a "Check Engine' (MIL). I also got DTC 1684, 1687 (No BUS messages received from the Mechanical Instrument Cluster (MIC) for approximately 25 seconds) and got 1695 again (No CCD/J1850 messages received from the body control module.)
The only way out of this was disconnect power to reset the computers. I guess it's all over once the MIL turns on. After resetting, as long as I started the car at least twice a day, it would work without losing the bus or turning on the MIL but the fuel gauge error was present. Leave it sit longer than about 14 hours and it would crash requiring reset to get rid of the MIL and lose the NO BuS message. The furthest I drove it when this was going on was a mile.

This behavior made me think to check the battery. It read 12.22 volts. After a fresh reset of the computers, I put a charger on it and fully charged it. It started and showed no errors at all. Then I let the car sit for a few days and repeatedly started it. It ran just fine without doing the NO BuS/MIL crash and burn. I left it sit for another day or two then took the car for a ride. 75 miles with 6 stops. It repeatedly gave me the dead fuel gauge/fuel warning light but would recover after a while. Otherwise, it did fine. I noticed I could bring it out of that error condition by adding an an electrical load. Turning on the parking lights, flash the brights, crank up the AC blower, activate the brake lights, etc. would ring the chime, the fuel gauge would read properly and the fuel warning light would go out.

After that trip and leaving the car sit a while, it never went to the bus error or setting the MIL but the fuel gauge error came back when just starting/running in the driveway and down the road and back. It also wouldn't come out of the error condition by adding an electrical load like it did on the short road trip. I noticed the battery voltage went down to 12.6 and it also re-set DTC 1695.

So the new observations indicate when the car was started with a battery voltage of ~12.2, it went berserk with "NO BuS" and "MIL" errors.

When initially started with battery voltage 12.5-12.7, the fuel gauge/warning light problem is in effect and shows various levels of dysfunction.

If the car is initially started with battery voltage above 12.7, there is no problem at all with anything. It's perfect.

The alternator tests good. It's putting 13.6 into a fully charged battery.

So, I still don't have the foggiest idea on what's going on or where to look but it seems as though the car requires a fully charged battery and needs a lot of electrical power to overcome some sort of resistance or corrosion that may be influenced by high humidity. The less initial electrical power available on initial start up, the more demented this car becomes.


Is this making sense to anyone?
 
#14 ·
Intrepid dementia

Another update. I'll continue to add info to this thread for my reference and for the benefit of anyone else who may experience such a problem

I was taking the car to town yesterday morning. Battery voltage before startup was 12.79. Before I got all the way out of the driveway I lost the fuel gauge, then the dash started lighting up like a blinking Christmas tree. I went down the road and quickly got the no bus message with MIL. So the previous idea the no bus error is related to low initial start up voltage seems to be invalid.

This went away quickly, including the MIL. I drove for a mile before I turned around. Before I got back home, there were many instances of no bus with MIL but now this error is somewhat recoverable because the the MIL turns off when the no bus message goes away

In the evening, I took another short ride but there were no more no bus/MIL incidents but I had the fuel gauge error with loss of control of the ATC display The controls would work this time and allow changing of settings, recirc, manual/auto modes, etc. but no changes were reflected on the display and the AC wasn't working very well. Most readings of the EVIC were no good. When I reached my turnaround point and stopped, the car chimed and the fuel gauge came back online and everything worked normally for a little while until the fuel error began again. After this, putting a load on the electrical system would force normal operation of everything again but it wouldn't last long.

This morning, I took it for another short ride and it was back into the intermittent no bus/MIL mode but again, when the bus came back on line, the MIL went away. On this ride, I was only able to get the fuel error to go away once and only for a very short time.

A second test session today revealed the same behavior as the second session yesterday. Fuel gauge out/fuel warning light on. Coming to a stop or applying an electrical load unreliably rings the chime and brings everything back on line. When parked and idling, the same thing happens but more reliably than when driving. Stuff quits, turning on the lights or increasing blower speed rings the chime and makes everything work.

So, I guess the next step is get me some contact cleaner and start tearing into it to see if I can find bad connections with corrosion and/or bad wires.
 
#15 ·
It can't be this easy

I won't have any contact cleaner until I go to town again but I opened it up to get at the BCM. I simply jiggle tested the plug connections for security and that made a difference. On a 5 mile test drive there was only one fuel gauge error and that corrected itself in seconds.

We'll see what it does in the morning. It doesn't seem to like mornings. Maybe it is something as simple as some corrosion in one of those BCM connectors.
 
#16 ·
Nope, it's not that simple. Sometimes it's perfect but more often these days it's circling the drain. I'm thinking the brutal heat and humidity this month is a big influence. Regardless, screwing up is good. A more reliable error should be easier to diagnose. My brother's shop doesn't have the DRBIII but the man who did the pre-purchase inspection for me 15 years ago does. I'll bring the car over to him next week.
 
#18 ·
I never did get this car to work properly again. Most of the time it did okay but continued to have the "seizures" so I rarely drove it. I only put another 1000 miles on it since I started this thread. I finally gave up on it and sold it for $900 this April, a month before the insurance came due again. II still loved the car but I got tired of paying insurance on a yard ornament.
 
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