[sadistic]

is it posible for the alt to put out more power as it gets older? most of all running a stereo 4 ga off the stock alt? i was wondering if the voltage reg was dying or if the alt wireing isolation was breaking down? i started playing with my stereo and the stock alt voltage went up go figure. the p1401 came back after 30 miles of driveing but instead of the brown white wire off the brain being 5.4 volt after market alt. it is now 5.11 off by .01 volts. for the stock alt. trying to figure out the code before i add the after market alt back into the car

 

[19065]

P1401 : Differential Pressure Feedback Electronic Sensor circuit High Voltage

I guess it would be possible for the alternator to send too much voltage if the voltage regulator went bad

but I couldn't make any sense of it happening if the wiring was breaking down

unfortunatly Im no expert so Id wait to see if others agree

 

[zeptoplix]

You should really try the other forum, but I'll answer this for you anyways.

I've been told, that if one of the diodes goes bad it can result in a fluctuations in the voltages. Example, old alternator, voltage would spike at like 15.5 or higher causing my amps and accessories to shut down.

 

[shoz123]

Voltage above 14.7 is a bad regulator. Diodes will cause flickering but not excessive voltage.

Usually a new alternator/regulator will put out 14.7 volts. As they age this will drop to the mid 13s when it is time to replace.

Don't know what year you have but the PCM gets involved in the voltage regulation of the newer cars.