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Electronic control and heater problems

I have a 2008 Dodge Charger V6 2.7L. When I was driving it the electronic throttle control light came on. I have changed the electronic throttle body but the light still comes on. Also the heater is blowing cold air. The car has a P2181 code which is coolant system performance. I’m thinking the thermostat. Came the two problems be related?

When was the last time you checked your coolant level? If you haven’t, I strongly urge you to do so immediately. You may be running on very low coolant, a destructive way to run and engine.

Yes, it might be a T-stat… but I suspect more. I always prepare for the worst and hope for the best. You’re going to need to be sure you have coolant BEFORE driving the car to a shop. The shop will need to pressure check for system leakage, including possible pump leakage, check for T-stat operation, maybe check flow of the pump and “map” the radiator for possible clogged tubes, and maybe do more. It may require checking for pressure leakdown of the cylinders. Let’s hope not. Let’s hope it’s just a cooling system issue.

The cool air from the heater is a bad sign that your system is low or empty. See above.

The throttle body code problems are probably unrelated, but the ECU does include engine temp in its algorithm, so it is possible that a bad temp sensor signal is causing the ECU to detect a mismatch between the signals; it may be sensing that the throttle position sensor signal is inappropriate for the temperature. The ECU generally ignores the upstream oxygen sensors while the engine is cold, and if the engine temp signal is out of whack it can have other implications.

I suggest you fill the cooling system, burp it, get the vehicle to a shop, tell them everything, and let them diagnose the problem. You MIGHT simply have a bad T-stat, but the implications of having a more serious problem, and the likelihood that you do, mean that you need to get this properly diagnosed ASAP and not make any assumptions. You could be damaging your engine as you drive.

Let us know what the shop finds. We do care.

If this car is a drive by wire design, the throttle valve angle inside the throttle body is constantly checked by the engine computer to make sure it matches what you are doing with your foot on the gas pedal. So it’s possible the problem isn’t with the throttle body, but instead the accelerator pedal sender unit is sending faulty data. The cooling system problem could possibly be related so it probably makes sense to fix that first, as doing so may also eliminate the throttle problem. I don’t think that’s going to be the case however, I think you’ve got two separate problems. If any work has been done with the cooling system lately, my guess is you’ve still got air trapped somewhere. It’s particularly difficult to remove all the air on a low slung car like yours, may need a special procedure or special equipment. There was a post here from someone with a Nissan truck as I recall who wasn’t able to get the air out of the cooling system no matter what he did. He finally got it out by jumping through a bunch of hoops as detailed in the truck’s shop manual. That’s an unusual thing for trucks, but not for low slung sports cars.