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  1. #1
    Join Date
    Jan 2020

    Default climate control acting up

    The temperature just dropped like a rock in the Dallas area 01/02/2002. And my 06 XC90 4.4l isn't blowing hot air in the cabin. If I fiddle with the controls for a while: change vents, change fans speed, temp left side, right side, change to automatis, back to manual, etc., it will eventually start working again. This takes 20-30 minutes of trying.

    I discovered that I may have caused the ECC to malfunction. August 2021 I had a vacuum leak somewhere in the engine compartment. Codes P0171 P0174. After finding and fixing multiple leaks, I disconnected the battery for 30 minutes in order to reset all computers (and reset error counters). I learned today that I (probable) did not follow the proper procedure for battery disconnect/reconnect. The ECC was probably still active when disconnect took place.

    Does anyone know how to reset the ECC without using a VIDA and VIDIS?

    Any advice would be greatly appreciated!

  2. #2
    Join Date
    Jan 2020


    Update on the climate control acting up post.
    The Engine Auxiliary Water Pump, (AKA heater coolant pump, coolant pump, etc) is not running.
    2006 XC90 4.4L, all options except Nav., 180k miles, runs near perfect except for the heater problem.
    This problem was discovered about a month ago when my wife reported that there was no heat in the passenger compartment. The ECC was set on high temp selected on driver side and passenger side.
    This is what has been done to date:
    1. Connect Vida 2014D, read codes. No codes related to the climate control or cooling system.
    2. Check all functions of the CCM: blower (fan), temp selectors, automatic mode, all other modes. OK. A/C works fine.
    3. Remove and test the temperature thermistor in the CCM and compare it to a new NTC 10 kΩ @ 25C specs (NTC Thermistor Characteristics Curve). Same. Reinstall the thermistor. Check the thermistor fan. It works.
    4. Note: engine thermostat and coolant was replaced Aug 2021. System was flushed. Engine reaches middle of dash gauge, normal.
    5. KOER, warmed up, coolant hoses on firewall (to heater core), stay cool until the car is driving for 15-20 minutes, then begin to warm up to 60-70 F. This is when its 25-30 F outside.
    6. Check the coolant pump (in left front fender well), not running. Check + voltage to pump: no voltage. Check ground wire: no ground.
    7. Flush the heater core just in case there is blockage. Clamped the inlet and outlet hoses before removing. I used the boiling water method to flush. Add Prestone coolant flush to heater core. Reflushed the core. Used compressed air to blow out the core (through the inlet port first). Very little crud came out. Reversed the test hoses and repeated the flush process. Some crud came out the inlet port with the liquid. Blast repeatedly with compressed air and it burped up a wad of crud. Reinstall coolant hoses. Top up lost coolant.
    8. KOER, same results as step 5.
    9. Test the coolant pump operation: disconnect the plug from pump. Hot wire the pump to the battery + and ground in the engine compartment. The pump works as it should. Leave it hot wired. KOER. Within 60 seconds the air at the vents in the car went to 110 F!
    My Vida 2014D doesnt have wiring diagrams. And Vida didnt provide any real help in explaining how the pump gets turned on and off as conditions change.
    I searched for hours trying to find a wiring diagram that would reveal where the 2 wires to the pump come from, BCM, ECM, ???. The + wire is black. The wire is light gray with red stripe.
    Any help would be greatly appreciated.

  3. #3
    Join Date
    Dec 2009


    Fuse 20 in the CEM is connected to item 6/113 (the aux pump 30776243) with a gr-r wire. Have you checked fuse 20 in the CEM? The pump runs all the time I guess - there are no signal wires from the CCM to tell it to run - and what signal would it use?

    Anyway I have several jpg attachments for documentation - I've uploaded hundreds here previously, but this website gives an error when I try - if you ask on swedespeed or volvoforums I can upload wiring diagram pages there -
    Last edited by hoonk; 02-04-2022 at 04:44 PM.

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