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OBDII fuse question

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Old Mar 11, 2009 | 09:02 PM
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OBDII fuse question

2005 F350 King Ranch Dually Diesel...
I just bought the truck, and found out the power port and the cigar lighter do not work. I'll check the fuses tomorrow, but have a question about the cigar lighter fuse. The manual states that the fuse for the cigar lighter also powers the OBDII. My question is this... if the fuse is blown, how does it affect the OBDII? Do you just lose power at the OBDII port, or is the OBDII non-operational all together? What are the main functions of the OBDII anyway? I believe it is supposed to perform diagnosics on the engine. If the OBDII fuse is blown, will I still get fault indications on the instrument panel if faults occur?
 
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Old Mar 11, 2009 | 11:00 PM
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The function of the OBDII port is to link a reader to the ecm. The ecm actually performs the diagnostics on the engine. The ecm will still function with the fuse blown, but you will not be able to pull up codes and readings without the fuse operational.
 
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Old Oct 10, 2010 | 05:48 PM
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Originally Posted by 07FX4
2005 F350 King Ranch Dually Diesel...
I just bought the truck, and found out the power port and the cigar lighter do not work. I'll check the fuses tomorrow, but have a question about the cigar lighter fuse. The manual states that the fuse for the cigar lighter also powers the OBDII. My question is this... if the fuse is blown, how does it affect the OBDII? Do you just lose power at the OBDII port, or is the OBDII non-operational all together? What are the main functions of the OBDII anyway? I believe it is supposed to perform diagnosics on the engine. If the OBDII fuse is blown, will I still get fault indications on the instrument panel if faults occur?

07FX4 --

Did you ever resolve the power port and the cigar lighter issue???


biz
 
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Old Oct 10, 2010 | 08:42 PM
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I sure hope he did after a year and a half!!
 
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Old Feb 17, 2012 | 10:06 AM
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Any additional feedback on this issue would be greatly appreciated! I'm having the same problem on a 2000 Diesel Ex. I would never have even checked for codes and found a non working DLC if I haven't noticed a big drop in MPG. After reading this post, I checked the cigar lighter and indeed it doesn't work. I will find the fuse and change it out today. But now wondering if at all this might effect the mpg/mpg overhead display?
 
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Old Feb 17, 2012 | 05:41 PM
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It won't. The only thing that fuse does is provide power to a pin on the DLC, so that devices plugged into it can have power. Nothing more.

All of the diagnostics, etc are handled by the engine, transmission and other computers.
 
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