2002 V40 ECC control panel acting irratically

steenbro · Post by **steenbro** » 14 Feb 2012, 11:42

Hi all,
I have trawled the web trying to find a solution to my problem and found this forum to be the most extensive Volvo site I could find. So what else to do but register and hope somebody can help:
My 2002 V40 2,0T ECC control panel will not start until the car has been running for 10 to 30 minutes. The A/C, rear windshield heater, seat heater and recycling buttons are 'dead', and cabin fan is not running. By watching the LED's on the buttons activated they flash simultanious very irratically as if it tries to start up (not flashing as if in error mode). After 10 to 30 minutes it usually start up normal and all is OK, but sometimes when it starts the cabin fan runs at high speed on all settings except 0 (where fan and A/C stops), still the rest of the controls works fine. I have replaced the blower resistor (actually a transistor) and removed the entire panel and cleaned the connectors, but no luck. Do I replace the control panel? Is this possible without doing a software reload? Looking forward for any hints!

/Steen

Post by **regent** » 14 Feb 2012, 15:07

Steenbro,
Pull the codes with a Volvo scan tool, it may be something smaller such as a button stuck or coffee spillage than having to replace the panel. The panel can be disassembled and cleaned, just follow the Battery disconnect - reconnect procedure very carefully. If you replace it no software reload is required for the CCM but you may need to reset/initialize the UEM.
Cheers

steenbro · Post by **steenbro** » 16 Feb 2012, 10:20

regent,
Can you please explain the procedures for battery disconnect-reconnect and UEM reset? (what does the UEM do?) When cleaning the connectors to the unit I just unplugged it. Does it have memory that is not cleared when disconnected?
/Steen

Post by **regent** » 16 Feb 2012, 12:22

UEM: Yes, the Upper Electronic Module does have the tendency of locking up when you play with the battery or if something else fails, thus freezing the sunroof and certain other functions that it is responsible for. After battery re-connect, the UEM may need to be cleared/initialized with a scan tool which basically erases codes that have been stored; however often times it is possible to do that with the simple 'lock-unlock three times via the key fob'. If you are replacing a module (for example the Alarm Siren Module, which has its own 'brains'), the UEM would not want to 'talk' to it and will misbehave unless you clear some codes with a scan tool (required).

Battery: On the P2 cars, you should wait a good 10 minutes after removing the key from the ignition with everything turned off before disconnecting the Batt Negative. When ready to re-connect, the key needs to be in position II (ignition ON). Ensure that nobody is inside the car when re-connecting the battery to prevent injury in case of airbag system malfunction. Then re-attach battery negative. The engine and transmission modules may need 'to relearn some of their habbits' during the first couple minutes (about half a mile or so) after takeoff.

I am almost positive, but would want to confirm if this same applies for your MY, and then will send you the battery procedure as soon as I get back home.

Thanks

Post by **regent** » 16 Feb 2012, 15:08

Battery Disconnect Procedure - Attached

steenbro · Post by **steenbro** » 18 Feb 2012, 10:08

Thanks, I'll give it a shot next weekend when I'm back home.
/Steen