These 41 and 46 codes on my '90 Dodge B250 van are driving me crazy!?

Question

I've been screwing around with this van for 2 weeks.
According to what I've read about Mopar fault codes, 41 and 46 both pertain to the charging system, one indicates that the field circuit is open or shorted, the other that the charging voltage is too high...I've measured 14.8 to 15.0 volts at the battery with the engine running. That seems OK to me.
If I'm wrong, please offer advice on how to correct the problem and clear these codes.
I recently replaced a coolant temp sensor to clear a 22 code and bring the idle back to normal range. Now the van seems to run OK at idle but while driving the idle speed is increasing to the point where it takes double the effort to stop. Also when you come to a complete stop and shift to Park, the engine races.
As a result of all this, (see my other post) the engine is running hot and getting really bad gas mileage.

I'm completely lost!

Answer 1

You might have a problem with the regulator. Unfortunately, these are located in the power module, (ECM,) and cost over $100.00 to replace. It might also explain all the other erratic behavior. Did you clear the codes after you replaced the coolant temp sensor? On that year all you have to do is disconnect the battery for about a minute to reset it. I've always found that disconnecting the negative battery post while working on the electrical system is a must. It resets the codes while you work. Try leaving the negative post disconnected to a few minutes and then operate the vehicle after you reconnect it. If the check engine light comes back on read it again, that way you might erase any irrelevant codes. You might also check your grounds. You have to have 3, 1 to the engine, 1 to the body, and 1 to the frame. You might also have a problem with a stuck thermostat. If it's running too hot your engine might race because the computer is sensing the engine is hot so it's telling the engine to run faster to circulate the coolant.