I’m getting a code - U0164: (Lost Communication With HVAC Control Module). This is a STR with the Nav screen, on the screen it lists COMMUNICATION FAULT Please Consult Your Dealer. While everything works fine on the radio once I click climate that message pops up, I took the glove box out and the module is there, I’ve removed it and plugged it back in, replaced battery, done 3 hard resets to no fix. The small screen also shows no ext temp or anything it just lights up green

 

Does the screen mess up only in cold temperatures?
Just a guess but as things age the screens become problematic with temperature.
Any chance you can get a cheap used one to try swapping units?
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No, it doesn’t do it in just cold climates

 

Little chilly out, anyone know the fix to this issue or where to start?

 

http://jagrepair.com/images/AutoRepa...cal-2006on.pdf

ATC\ACCM module is on CAN. check power and ground then go across can hi\lo at the connector make sure you get 60 ohms. when the heater valve is jammed for a long time it usually just burns out the driver in the ATC module but if it's really bad maybe you smoked the whole board.

 

Perfect, if I’m looking correctly. The accm is the black box that is behind the glovebox?

 

In the Christmas spirit:



Back to your car. What is the present output from the HVAC system?

I'm thinking if the control module had totally failed (or wasn't receiving power), the valves within the DCCV spring-load to the full open position and would provide maximum heat at all times.

Now this next bit is a just a hunch, but if the only portion that failed was the feed to the control/display screen, I'd think the system would stay in the last commanded position, as if you hadn't adjusted the output temperature. For example, my '02 has the simple combination display/control module. I usually leave it set to 72 or so. If the dot matrix display section were to fail, the rest of the system would hopefully remain set at 72.

That's why I'm curious how the HVAC system is behaving, even if you can't see the display or adjust anything.

 

When you click on climate the message “communication error” pops up, I have no air, a/c, heat, defrost or anything of that sort from my Nav unit, radio and cd changer works fine and stuff. And yes it is a bit chilly lol!

 

Hmm, apparently my hunch was less correct than usual.

Got three fuses for you to check:

Primary junction box (inside the cabin, just forward of right front door) - fuses #14 and 20
Front power distribution box (under the hood) - fuse #32.

 

checked those fuses and some others just now, all look good

 

Next step would be to do the electrical checks xalty suggested in post #5 above. Look for any signs of corrosion or other damage at the module connector, too.

If all good, you’ve probably got a bad module. Don’t just gloss over the electrical checks, as it’s pretty rare to have a bad module.

If not too hard to open it up, it might be worthwhile to look over the module circuit board with a magnifying glass. Look for any discoloration from overheating. Inspect for any cold solder joints. They are prone to cracking and will have a dull appearance, instead of the normal metallic shine.

 

I opened up the rccm box, everything looks perfect no burnt traces or anything burnt

 

verify power and ground at the connector

 

Hooked my multi meter I am getting power to the big connector

 

2 pins on the big connector are giving me 12V

 

Since I am getting 12 volts from two pins on the big connector I’m guessing I’m getting power. I’ll have to check the diagram again to which two pins. So the U0164 code and getting power should lead to bad module? Only thing is do these modules have to be coded to the car? And has anyone’s just went completely blank like this?

 

Update:
new climate control module fixed it and is working good

 

Hey great news!
I hate to suggest module replacement right off the bat as it's not that common.
If anyone is following another method is the RCCM can be repaired and even upgraded so the DCCV won't blow it up again if it goes bad.
AC Module Repair
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