I just wanted to add this to the knowledge database in case someone else experiences it in the future. My problem is now solved.

Background: My car is a 2000 VDP S/C. I saw "engine failsafe" flashed on the IP one day in the recent past, which worried me. It disappeared at the next restart, so I just waited to troubleshoot it when it appeared again. I was prepared to replace the brake switch or throttle body, the two most common causes for that message.

But then last weekend I was bombarded with messages in the info center--engine failsafe, gearbox fault, trac not available, asc not working, low brake fluid, all in a frightening rotation. The climate control beeped and displayed "Er," the shifter interlock did not release with the brake, and pulling codes I got a P1638 "Can token message missing."

I already knew that my shifter night illumination had stopped working a while ago, and I noticed that the red shifter indicator light was now also missing. I dove into the console on a hunch and found that the ribbon cable that goes to the circuit board in the shifter illumination module was hanging by one contact. Squeezing the cable back to the board cleared all errors.

One $250 LNC-6195-AC later, all is well.

If you look at the circuit board, there is a clock chip on it, so it definitely communicates on a timed bus--mind-boggling complexity for some nighttime illumination.

I am still in total amazement that something so seemingly inconsequential as a shifter illumination module can wreak such havoc with the internal systems.

TTYL
David

 

And what, pray tell, is the LNC-6195-AC?

 

It's the entire illuminated shift gate module, the black plastic PRND432 with LEDs inside.

TTYL
David

 

Thanks. So the entire problem was not just due to the slowly unplugging cable, eh? Too bad. At least the CAN bus failures are now gone. Did you do something to prevent the ribbon connector from coming loose again in the future?

 

The ribbon cable is actually soldered directly to the circuit board. All my pins were sheared at the solder joint. So it wasn't just unplugged, the contacts were broken. I'm not sure why it failed, there doesn't seem to be any stress on that connection. I guess 10 years was just the lifetime of mine.

When I said I squeezed it all back together, I was just temporarily restoring contact, the permanent connection was ruined. If someone were really handy with a soldering iron, it could probably be fixed--the wires are pretty tiny and I didn't feel like messing with it. I just bit the bullet and bought a new one.

I'm fairly confident the spurious "failsafe" I got last week is related to this--I'll just have to wait it out and see if it reappears.

TTYL
David

 

Always appreciated to have a member 'summarize' the issue and document the resolution, thanks so much!

And even the part number and 'current' price...nice touch.

 

The illumination module communicates gear position to other modules. That is why it is networked. The super charged cars use a linear switch on the side of the j-gate because the Mercedes trans needs a different signal than the ZF in the NA cars.

 

Thanks for the explanation... hang on to it. The soldering would be quite easy, and I'm sure you could get someone that is proficient at it (I'm too far away) to do it for next to nothing.

 

The clock chip might just be for PWM (pulse width modulation) to electronically control the light brightness.

 

That would make sense except for the O/P's symptoms - total bus panic with the board's leads broken - AND Real_Tech's description above, that the board communicates shifter position to other sub-systems - it's CAN bus...