How to Fix a P0191 code?

SilverBack76

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Apr 30, 2009
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Hey guys. I did a search on this code that has popped up twice on me, a P0191 Fuel Rail Pressure Sensor Circuit Range/Performance. There are about two things they say to do, 1) take it in to get reflashed, 2) replace the rail pressure valve/sensor. Now my question is what would cause that, a spike in rail pressure? And is either of those two options a fix. I need to get a RP gauge on this week but what sugguestions do you guys have? Thanks.:Cheer:
Brian
 
that's a very common code to come up. Can't tell you the exact cause ( guessing the RPS )but, I know I get it a lot too. I just clear it and go on my way. It comes back every once in a while so I just clear it again.

This is what the service manual says about it.....

Possible Causes
OTHER DTC’S PRESENT
FUEL RAIL PRESSURE SENSOR
FUEL SYSTEM TAMPERING
INTERMITTENT CONDITION
 
new flash should take care of it. does it set on start up?

Not sure, I usually find it after I have another code pop, so I am clearing it tonight and I'll start her up and check it.

So this is not a O"Crapp thing. That is good to know. Could this be cause by my fuel pump not suppling the right pressure? Thanks Ty.

And Vielen Dank! I swear I should invest in that stuff.

Brian
 
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the only real reason to cap it is to avoid dealing with it " when " is blows. We're running higher psi than a stock truck so most are almost guaranteed to blow their relief. You don't have to do it but, at some point, you will be replacing the stock valve.
 
it can't hurt. Like I said, you can wait till something happens ( truck won't run well and will have issues starting ) or, just get one and not worry about it.
 
it can't hurt. Like I said, you can wait till something happens ( truck won't run well and will have issues starting ) or, just get one and not worry about it.

Thanks, I just finished reading the thread on Max rail pressure, and saw your responce to those questions. Are you at Garmons working on your truck? If you are would you mind me coming by to check it out. Thanks Brian
 
no but, my truck is there. You're welcome to go have a look see. The motor is kinda disassembled so there's not much to see there. It's not very clean either :doh: Just tell Jeff I told you to give it a once over.
 
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