Seems like you may have multiple problems with your vehicle? If the heater does not blow hot air when selected and vehicle is overheating then I suspect that you have little to know coolant in the cooling system? You have a small radiator called the heater core behinde the dash that has hot coolant flowing through which gives you your heat. If you have no coolant or water flowing through, then you will have no heat. As for the check engine light and reving up high there is a good chance that all your problems may be related. Your thermostat could be stuck either open or stuck shut? So I suggest you replace the thermostat and gasket. As for the high idle, replace the engine coolant temperature sensor and you should have easy acess once you remove the thermostat housing. What could be happening an I have done a few repairs for this, is that the ECT sensor has very high resistance/ open circuited that the engine control module will interpret the signal it sees as a very cold engine. So what the engine management sytem does is races the engine up and makes the car run very rich to try and warm up the engine faster and get the catalytic converter hot. If you were to have the codes scanned by Volvo you would most likely see the following codes. ECM-A1 ECT faulty signal and maybe an ECM-15 ECT sensor high resistance. Dont drive too long with this condition because you can end up having severe problems, one is you can damage the cylinder head from overheating and you could damage the catalytic converter from too much raw fuel being dumped from the running rich condition. Hope this helps you a little and check that the coolant is full and flowing and have the engine control module scanned for codes to try and verify that you are actually having the problems I have describes? Good luck to you and keep me posted.
Saturday, May 8th, 2010 AT 1:53 AM