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Too much voltage from capacitor?

1K views 4 replies 3 participants last post by  JoelJackson 
#1 · (Edited)
Recently installed a capacitor to fix dimming light / power loss issue, while I was at it I charged the battery. After the install it was like the new setup shocked the car or something, had too much voltage to a few systems and the car was doing strange things (ie. Auto windows not working). After a few days it seemed to even out and things started working normally again but a code stuck, p0406 EGR sensor A circuit high. I guess my question is has anyone else installed a capacitor and run into voltage problems or is the code just a coincidence? Any help is appreciated:laugh2:
 
#2 ·
You're not going to get too much voltage from a capacitor; that's not how they work. If it was completely discharged when you installed it, again depending on how big it was, it could possibly load down the electrical system until it charged up, but it should charge up pretty quickly and stabilize, and it wouldn't take more than a few seconds to do so.

Where did you install the capacitor, and for exactly what reason, like lights dimming when the radio is cranked up?

On the other hand, if the capacitor was charged up to a higher voltage (>15V) when you installed it, that higher voltage could have damaged something when it was applied to your 12V line. If that happened, you may have damaged the sensor that is giving you the code and caused it to "short" (I'm using this term loosely because it wouldn't have been a real short circuit, more like an abnormally low resistance) and it could have been getting very hot while it was causing the rest of your car to malfunction. After a few days of running like that, the sensor could have overheated to the point where it finally burned out and opened up, allowing everything else to return to normal. The code you are getting indicates an open circuit, which could be anything from a bad sensor, a bad connection, or a broken or melted wire. The easiest thing to do would be to replace the sensor and see if the fault code goes away. If not, start checking the wire harness and pray it's not the computer...
 
#3 ·
I had charged the capacitor to 10v before installing, it was recommended that I charge it to 12v but I got impatient and was pretty confident charging it wasn't going to make a difference for the install. It's just a simple 1 farad cap and I use it as a buffer for voltage spikes from loud music. I'm going to go ahead and replace the EGR valve, if I'm not mistaken the sensor is part of the assembly?
 
#4 ·
The auto windows stopped working because you must reset them after disconnecting power.
To reset just lower the window all the way down and keep holding button for over 1 second after it has bottomed out. Then do the same for window up.
The EGR code might clear itself if you try disconnecting your power and reconnecting it again (this includes the capacitor).
 
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