Chrysler Repair: overcharging or not????, dodge caravan, engine controller

Question
I got a 1992 dodge caravan the volt gauge reads extremely high voltage at an idle when nothings on switch the lights on and its still high but goes down a bit checked voltage at battery and its normal could there be a problem with PCM or ground problem I'm stumped on this one            thank you

Answer
Hi Brad,
If you believe your voltmeter to be accurate then I would question the accuracy of the dash gauge. WIth the engine idling and all accessoried turned off the voltage across the battery should be 14.45 to 14.95 V in the wintertime temperatures we are experiencing. The other way to get an answer is to see if the PCM has observed any problems in the voltage control system. The most useful thing to do would be to try to get the fault codes that may stored in the engine controller memory to readout. Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout". The fault codes that might be related to the charging system running at too high a voltage are 41 (field coils of alternator not responding to commands for regulation of output) and 46 (output voltage too high). So see what that readout tells you as well as your voltmeter. Then let me know what you have learned for further evaluation.

Roland