QuestionQUESTION: On my 1994 Chrysler Lebaron GTC (3.0 engine), My check engine light came on about 2 days ago. Also the ammeter needle is almost all the way to the negative side. I took it to advanced auto parts. they did not have the correct type of diagnostic machine to check for error codes. I did the check by turning the ignition on & off 2 times and then on again I came up with a code of 4155. there book only gave 2 digit codes but it said it was the charging system which I suspected gentleman came out and checked the alternator and battery. the alternator was not kicking out any amps. I purchased a new alternator and new belt and installed them.I am still getting a check engine light warning and the ammeter still shows negative. when I check the codes again I get either 3-4-1-5-5 or 1-2-4-1-5-5. I have gone on line to a sight and all there codes start with a letter and I don't know how to determine what the letter would be. Also I understand the voltage regulator is in the computer. Can You please help me. This car belonged to my late wife and is more or less a hobby car. Thank you
ANSWER: Hi Victor,
The present codes are 12 (which means the battery was disconnected recently (probably when you replaced the alternator, correct?), 41 which is saying that the circuit that activates the field coil of the alternator (which turns it on and off as needed) is at fault, and 55 which means 'end of code readout'.
So about the 41 code: The field wires are dark green/orange and the dark green. The dark green/orange wire should show 12 volts on it when the engine is running as that is the wire that powers the fuel pump and the spark plug coils. So measure between that wire and chassis ground with a voltmeter to verify that it shows 12v.
The dark green wire is connected to pin 20 of the powertrain control module's 60-pin plug so verify that the connection is patent between the alternator and that pin of the big plug using the ohm function of a volt-ohm meter. One of those two measurements should be wrong if indeed the field coil is not being activated. Maybe a break/disconnect in one or the other so check over the wires in question to see their condition.
Let me know what you find.
Please read the PS below and respond to it.
Thanks,
Roland
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QUESTION: Where can I purchase a new or rebuilt sbec for this auto?
ANSWER: Hi Victor,
I would start at eBay. BUT you don't have a fault code in the "60's" which would tell you that a replacement for the SBEC is necessary. I would check over those two wires before beginning on replacing the SBEC.
Roland
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QUESTION: Where is the power control module located and can How do I check the wires as you described
AnswerThe powertrain controller is mounted on left side inner fender at the upper edge and has the large 60-pin plug. Check the continuity between pin 20 and the other end of the green wire at the alternator. Then start the engine and observe for 12v to be present on the green/orange wire at the alternator. If both those check out then I would suspect the field coil of the alternator is bad, given that you do show a 41 code which points to that particular circuit.
Thanks for the previous ratings and nominations, which you can do again if you like.
Roland
