Yesterday I had the truck and trailer all loaded ready to head for the job and started it ,it went to running like it was getting air or a bad fuel filter. I shut it off changed the big filter back by the fuel tank (1r0749) it didn't look bad about a half a thimble of water if that, didn't change the way it was running at all. So I checked the fuel pressure it seemed normal. So I hooked up my Actron code reader it said P0191 Fuel rack sensor.What to do now. By this time I'm starting to get a little shook. So I got my service manual and went to reading to find out what I could. It seems that when you shut off the engine if the fuel pressure does not fall quick enough it will set DTC P0191 and then you get bad fuel filter symptoms.So I cleared the the code after I'd done everything I could think of and when I cleared the code it took off and went to running great ever since. Does anyone have any input?????? Also the book said that if you start the engine and shut it off real fast you could set this code. I think that is what I might have done.

I guess there is not anyone familiar with this code. Thanks anyway I'll keep on searching. I hope it does not happen again. I'll see if I can find someone to check the balance on my injectors. I'm not sure that has anything to do with it.

Conditions for Setting the DTC
P0191
• The actual FRP is below 0 MPa (0 psi), or above 0.77 MPa (112 psi), when the ignition is ON and the engine is OFF.

OR

• The actual FRP is below 0 MPa (0 psi), or above 0.77 MPa (112 psi) within 70 seconds of the ignition being turned OFF.


Diagnostic Fault Information
Circuit
Short to Ground
High Resistance
Open
Short to Voltage
Signal Performance

FRP Signal
P0192
P0088, P0191
P0193
P0193
--

FRP Low Reference
--
P0191
P0193
¹
--

FRP 5-Volt Reference
P0117, P0462, P0522, P0652
P0087, P0191
P0193
P0118, P0653
--

Fuel Pressure Regulator Solenoid Supply Voltage
P0088, P0090
P0088
P0090
P0087, P0191, P2510
--

¹ Opens circuit fuse or opens circuit.



Circuit/System Testing
Important: Fuel pressure control will be disable if DTC P0087, P0088, P0192, or P0193 are set. Codes must be cleared to enable the device control.

P0191
•Turn OFF the ignition.
•Disconnect the ECM connector and the fuel pressure regulator connector.
•Test the fuel pressure regulator solenoid supply voltage circuit for a short to voltage.
•Disconnect the FRP sensor.
•Test the FRP signal circuit, the 5-volt reference circuit, and the low reference circuit for high resistance.
⇒ If all circuits test normal, replace the FRP sensor.

Thanks Bryce418 for the information on P0191. Since I reset the DTC IT has been fine. The truck has 73,000 miles on it. I will see about gettting that all checked.

my truck has been throwing a P0193 lately on and off. I thought it was a bad tune but that doesn't seem to be it. I did notice it has done it since it was been really hot and doesn't seem to do it on cooler days and or at night. Could fuel temp cause a problem?

My truck throws a P0101 intermittently, but during the winter it never shows up. I also notice I get this when it's warm and or raining. I had it in for service years ago for this and after 3 Baro sensors, and 2 MAF sensors, the dealership then said it was the Banks Kit causing an over boost. Which is code for "We don't know :wtf1:it is, but we're pretty sure it's the aftermarket stuff." :rolleyes:

I have been told that it is my programming in the PCM as the '01 software is bugy. I would get this changed but I really don't want my PCM locked where I can't get to it with EFI.

My wife's 04 Suburban started getting this same code and it turned out it was the MAP sensor, the DTC has not returned since (6 months).

my truck has been throwing a P0193 lately on and off. I thought it was a bad tune but that doesn't seem to be it. I did notice it has done it since it was been really hot and doesn't seem to do it on cooler days and or at night. Could fuel temp cause a problem?
I was reading a TSB and it mentioned this code:
DTC P1093 Fuel Rail Pressure (FRP) Low During Power Enrichment

Any chance you guys are dealing with a bad FP regulator?

I was reading a TSB and it mentioned this code:
DTC P1093 Fuel Rail Pressure (FRP) Low During Power Enrichment

Any chance you guys are dealing with a bad FP regulator?

I thought it was a P1093 code at first but after it kept coming up I realized it was P0193 which deals with sensor voltage. I have a PPE shim kit in my rail pressure relief valve so I doubt it's actually pressure itself

I was reading a TSB and it mentioned this code:
DTC P1093 Fuel Rail Pressure (FRP) Low During Power Enrichment

Any chance you guys are dealing with a bad FP regulator?

I thought it was a P1093 code at first but after it kept coming up I realized it was P0193 which deals with sensor voltage. I have a PPE shim kit in my rail pressure relief valve so I doubt it's actually pressure itself
Here is the rest of the info concerning "Power-Up" devices related to the FPR:

"Aftermarket companies have developed a performance pressure relief fuel valve for Duramax™ diesel engines. Refer to above graphic illustration. The performance pressure relief fuel valve attaches to the fuel rail in place of the OEM valve and will not allow any fuel return to the tank, giving 100% of the fuel to be available for additional engine performance. This may cause additional fuel related driveability concerns and may set the following DTC'S:
• DTC P1093 Fuel Rail Pressure (FRP) Low During Power Enrichment
• DTC P0087 Fuel Rail Pressure (FRP) Too Low

HTH some.

Here is the rest of the info concerning "Power-Up" devices related to the FPR:

"Aftermarket companies have developed a performance pressure relief fuel valve for Duramax™ diesel engines. Refer to above graphic illustration. The performance pressure relief fuel valve attaches to the fuel rail in place of the OEM valve and will not allow any fuel return to the tank, giving 100% of the fuel to be available for additional engine performance. This may cause additional fuel related driveability concerns and may set the following DTC'S:
• DTC P1093 Fuel Rail Pressure (FRP) Low During Power Enrichment
• DTC P0087 Fuel Rail Pressure (FRP) Too Low

HTH some.

Thanks for the info, I'm still working on the problem but will keep things posted as they develope.