PO620 code
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PO620 code
I have an issue with my Battery/Alternator light coming on in the message center every morning or after the car has sat all day. It doesn't come on if I go somewhere and get back in after a few minutes. I checked for codes and found that there is a PO620 Generator control circuit problem. Does the PCM regulate the voltage or is it in the alternator? I put a meter across my battery in the morning and watched it spike up to 18 volts on startup then drop to 14v. During which time, the SRS, and ESP lights come on momentarily. If anybody has any ideas they would be greatly appreciated.
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Joined: Oct 2004
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PCM - Powertrain Control Module. Some manufacter's utilize the PCM to regulate voltage. I thought that if the PO620 was stored in the memory that this would be the case. I'm not sure. It was at 18v for a couple of seconds. Then dropped down to 14v.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
P0620 = Generator Control Circuit Malfunction.
The regulator in the rear of the alternator is faulty. It should cut at approx 14.2 volts.
Benz does not use the ECU for charging control.
The regulator in the rear of the alternator is faulty. It should cut at approx 14.2 volts.
Benz does not use the ECU for charging control.
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Joined: Aug 2017
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2005 c230 kompressor
I have the same code p0620
I have a 2005 c230 Kompressor giving me the P0620 Generator Control Circuit. I really notice the rough idle , mainly while in drive and the foot on the brake. This happens when I turn on anything electrical. So my best course of action is to replace the alternator? Also Autozone tested my battery and it passed but the voltage regulator failed. Hopefully replacing the alternator does the trick. I havent had to put any repairs into this car yet other than maintenence. So ill be happy if its just the alternator.
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Joined: Sep 2016
Posts: 571
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From: New England! :-)
2005 C230K Sport Coupe
I have a 2005 c230 Kompressor giving me the P0620 Generator Control Circuit. I really notice the rough idle , mainly while in drive and the foot on the brake. This happens when I turn on anything electrical. So my best course of action is to replace the alternator? Also Autozone tested my battery and it passed but the voltage regulator failed. Hopefully replacing the alternator does the trick. I havent had to put any repairs into this car yet other than maintenence. So ill be happy if its just the alternator.
*BUT*, some people have had issues getting China clone voltage regulators that do not work, even though the seller says it's an 100% OEM voltage regulator.
Good luck!
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Joined: Dec 2018
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W203 200 kompressor station wagon
W203 200 Kompressor P0620
I have this error code showing up but the voltage is stable across rpm range, between 13,5 and 13,8. I have changed the voltage regulator just got n case and nothing has changed. This has been going for more than a year without any starting issues. Does anyone have the wiring scheme so I can start measuring things and checking earths? Thanks
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