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2000 Eldorado
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6 Posts
Discussion Starter #1
Hi ,
Have 2000 Eldroado
Service Engine Soon light comes on and DTC posts PCM B0101 ( MAF ) and B0621 ( generator L terminal circuit )
Car usually runs fine, but once and a while kind of hesitates then runs fine again

I had these symptoms last week. I replaced the battery and cleared all the codes and started fresh

I drove ~ 10 miles and get SES, PCM B0101 & 0621

The DIC says car is charging 14.2 to 15.0 Volts

Whats next - replace MAF sensor or look at charging system ??

HELP
Thanks
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Re: 2000 ELDO with Service engine Soon light and PCM codes B0101 and 0621 (HELP )

Your charging and steady state voltages are right on target. An automotive voltage regulator always sets a slightly elevated voltage output coupled with a regulated amperage rate to carry only the existing loads in the car - after the battery charge "shows" the voltage regulator the specified battery internal resistance. (A dead battery is essentially a grounded short in the charging system; a fully charged battery has high internal resistance) The "generator L circuit" is the output from the voltage regulator that extinguishes the DIC warning and/or the battery light icon. ("L" used to stand for "light") You might want to remove and clean the multi-pin connector at the alternator as well as inspect the wiring for insulation breaks.

In your car, with a divorced MAF, any air leak in the intake air ducting will set MAF codes as well as lean mixture codes. Check everything from the air filter box to the throttlebody for tight band clamps and no holes/tears.
 

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2000 Eldorado
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6 Posts
Discussion Starter #3
Re: 2000 ELDO with Service engine Soon light and PCM codes B0101 and 0621 (HELP )

Thanks SS409
I looked from the air cleaner to the throttle body, cleaned the trottle body before replacing the battery, all seemed good, clamps tight, rubber ducts looked solid - I will look again

Wonder why the PCB -0101 and 0612 set together/same time - the description don't seem related ?????

Gary SSBN 610&635
 

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2003 Deville
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22 Posts
Had a PCM 0621 code come into y DIC as the bathtub was failing - needs a new alt., and the code was only'current the battery light was on - if I checked the voltage and it said battery 13.6 OK it went to history, yesterday it was telling me that my battery was overcharging.
 
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