aircon problem.

vollic 75 · Post by **vollic 75** » 30 Oct 2005, 08:36

I have an air con problem with my Volvo S40 (2000 model).The RPM will always fluctuate between 1000 to 3500 whenever i switched on the aircon.During slow forward movement it causes my car to be jerky when the gears are engaged without the accelerator depress.And i can feel that my car is under power sometimes even my engine die off when i move off. It's worst of if the weather is hot.I've got the idling valve changed by volvo,the air con gas checked and the filter changed but it still persist.Does any one have this problem or similar also.

DW · Post by DW » 31 Oct 2005, 09:21

Might be an Air mass flowmeter (oxygen sensor) problem. When the air-conditionner is turned on, the load on engine goes up. To take up this load increase, the air mass flowmeter tries to increse the air supply to the engine.
If it's wrong, the fluctuation could happen.

vollic75 · Post by **vollic75** » 06 Nov 2005, 05:00

Thanks DW,
but i was also thinking could it be a faulty air con thermostat sensor,because i can feel that the fluctuation worsen whenever the aircon thermostat comes to work(meaning to regulate the temperature of the incoming air to the cabin).And whenever the rpm starts to fluctuate.Immediately either i switch off the aircon knob or select air con/fan button to air con off leaving just the fan blowing without cold air,the rpm immediately goes back to normal.

seanwil · Post by **seanwil** » 19 Jun 2006, 11:30

Hi Vollic75,

I am experiencing a similar problem to the one you reported in this thread and was wondering if you found the root cause and could let me know.
My car is a 2001 V70 2L Turbo. The rpm fluctuates up and down when idling by a few hundred rpm when the aircon is on.

Thanks

English Rose · Post by **English Rose** » 25 Jul 2006, 11:14

[quote="seanwil"]Hi Vollic75,

I am experiencing a similar problem to the one you reported in this thread and was wondering if you found the root cause and could let me know.
My car is a 2001 V70 2L Turbo. The rpm fluctuates up and down when idling by a few hundred rpm when the aircon is on.

Thanks[/quote]

Hello there,

My S40 T4 Turbo also has a problem which seems to be related to both the air conditioning and the radio.

When slowing up and approaching junctions, the revs drop dramatically and then the car stalls. This only seems to happen when the air con and/or radio is switched on and seems to be much worse in hot weather.

I should love to know what exactly is causing this problem and shall be so grateful if anybody has any ideas!

Many thanks.