fuel rail pressure sensor

Tired of shooting in the dark, really need some help. 07 silverado 5.3 z71

Problem all started when fuel pump died. Replaced fuel pump truck ran for about a mile then started to act up like it was starving for fuel. Dealer replace fuel control module that's under spare tire, reprogram. Truck ran fine for a day then light back on. Code showed rail pressure sensor was issue, dealer decided to replace fuel pump again. Well light is on again showing sensor, so I replaced fuel rail sensor. Clear code and light is on again for fuel sensor. Note truck runs great no issue, I also replace 02 sensors,plugs,wires and air filter. Clean map sensor and throttle body. Any help will be greatly appreciated, tired of dealer guessing. Sorry for rambling it's been a tough couple of weeks :banghead:

Tired of shooting in the dark, really need some help. 07 silverado 5.3 z71

Problem all started when fuel pump died. Replaced fuel pump truck ran for about a mile then started to act up like it was starving for fuel. Dealer replace fuel control module that's under spare tire, reprogram. Truck ran fine for a day then light back on. Code showed rail pressure sensor was issue, dealer decided to replace fuel pump again. Well light is on again showing sensor, so I replaced fuel rail sensor. Clear code and light is on again for fuel sensor. Note truck runs great no issue, I also replace 02 sensors,plugs,wires and air filter. Clean map sensor and throttle body. Any help will be greatly appreciated, tired of dealer guessing. Sorry for rambling it's been a tough couple of weeks :banghead:
You paid good money to the dealer they should be responsible for the repair. They need to put an oscilloscope on the fuel pump voltage. The computer pulses the ground to vary the voltage to control the pressure.

You paid good money to the dealer they should be responsible for the repair. They need to put an oscilloscope on the fuel pump voltage. The computer pulses the ground to vary the voltage to control the pressure.

Agreed. If they didn't fix the original complaint the first time, take it back. What is the code (numbers please) that keeps setting?

Agreed. If they didn't fix the original complaint the first time, take it back. What is the code (numbers please) that keeps setting?

code is PO 191 Rail pressure sensor "A" circuit Range/Performance Confirm.

I've spent plenty of time on google looking for answers to this problem. On another site there was a 08 with same issue, wasn't mention if it was resolved.

fuel rail pressure sensor is a 3 wire potentiometer.....5 volt ref.....signal and ground.....if module and sensor was replaced that leaves a connector or a wiring problem.would have to check 5 volt ref circuit.....the ground circuit.....and signal circuit for integrity.is truck still stalling?

fuel rail pressure sensor is a 3 wire potentiometer.....5 volt ref.....signal and ground.....if module and sensor was replaced that leaves a connector or a wiring problem.would have to check 5 volt ref circuit.....the ground circuit.....and signal circuit for integrity.is truck still stalling?

He beat me to it! I was just about post the same info...

He beat me to it! I was just about post the same info...

Truck not stalling or hard to start. Actually seems to run fine, little hard of mpg 15.4... Getting scan tomorrow at my work. Will post what shows up.

Tired of shooting in the dark, really need some help. 07 silverado 5.3 z71

Problem all started when fuel pump died. Replaced fuel pump truck ran for about a mile then started to act up like it was starving for fuel. Dealer replace fuel control module that's under spare tire, reprogram. Truck ran fine for a day then light back on. Code showed rail pressure sensor was issue, dealer decided to replace fuel pump again. Well light is on again showing sensor, so I replaced fuel rail sensor. Clear code and light is on again for fuel sensor. Note truck runs great no issue, I also replace 02 sensors,plugs,wires and air filter. Clean map sensor and throttle body. Any help will be greatly appreciated, tired of dealer guessing. Sorry for rambling it's been a tough couple of weeks :banghead:

THIS is the TSB about this very common problem .................


Subject: Malfunction Indicator Lamp (MIL) Illuminated, Intermittent DTC P0191, Slow Fuel Rail Pressure (FRP) Decay, Wiring Harness Connections, Voltage Fluctuations/Interruptions (Follow Correction Information Below)

Models: 2006–2009 Chevrolet Express, Kodiak, Silverado
2006–2009 GMC Savana, Sierra, TopKick
Equipped With Duramax™ Diesel Engine (RPOs LLY, LBZ, LMM)
Please Refer to GMVIS
This bulletin is being revised to update the reprogramming emission controller warranty coverage period information. Please discard Corporate Bulletin Number 09-06-04-022A (Section 06 — Engine/Propulsion System).
Condition
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65566)

Some customers may comment that the malfunction indicator lamp (MIL) is illuminated, or it illuminates intermittently.
The technician may find DTC P0191 set as current or in history. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65566)
Causes
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65578)

• A slow fuel rail pressure (FRP) decay rate may exist, due to an accumulated but harmless varnish buildup on the fuel injectors.
• The wiring harness connections may exhibit incorrect crimping, corrosion or poor terminal tension.
• Aftermarket electrical equipment may be improperly installed on the vehicle resulting in an interruption or fluctuation in voltage to the engine control module (ECM).
• The ECM monitors the FRP sensor voltage signal at engine start up. If the voltage signal is greater than (high fuel rail pressure) a calibrated amount DTC P0191 can set.
• The ECM monitors the FRP sensor voltage signal at engine shut down , expecting a decrease to a low voltage signal (low fuel rail pressure) within a calibrated amount of time. If the voltage signal is greater than a specified value within that specific time period, DTC P0191 can set.
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65578)
Correction
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65626)

Verify the model year of the vehicle in order to determine which one or both of the following procedures to utilize. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65626)
For 2006-2008 Vehicles – Diagnose Possible Slow Fuel Rail Pressure Decay First
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65639)
Important: DO NOT replace the ECM, the fuel rail pressure regulator, or the fuel rail pressure sensor for this condition.

1. Start and idle the engine.
2. Observe the Fuel Rail Pressure Sensor parameter with a scan tool. The parameter should be between 30-40 MPa, depending on engine coolant temperature (ECT).
3. Turn OFF the engine, and immediately turn the key to the ON position.
4. Using a stopwatch, observe the decay of the Fuel Rail Pressure Sensor parameter with a scan tool.
5. The Fuel Rail Pressure Sensor parameter should decay to less than 6.6 MPa within 15 seconds.
If the Fuel Rail Pressure Sensor parameter is more than the specified value within the specified time period, then reprogram the ECM.
Important: If a 2006-2007 LLY, LBZ vehicle has, as one of nine ECM module ID Part Numbers, Part Number 12632483, then reprogramming the ECM will not repair this condition. If a 2007i-2008 LMM vehicle had field action V1819 - 08142 ECM EEPROM - REPROGRAM ECM applied, then reprogramming the ECM will not repair this condition. All 2009 LMM's already have an extended rail pressure bleed down calibration.

A revised software calibration has been released to address this condition. Reprogram the ECM using the Service Programming System (SPS) with the latest calibration available on TIS2WEB. Refer to the SPS procedures in SI.
When using a multiple diagnostic interface (MDI) for reprogramming, ensure that it is updated with the latest software version.
When using a Tech 2® for reprogramming, ensure that it is updated with the latest software version.
During programming, the battery voltage must be maintained within the proper range of 12-15 Volts. Only use the approved Midtronics® PSC 550 Battery Maintainer (SPS Programming Support Tool EL-49642) or equivalent during programming. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65639)
For 2006-2009 Vehicles – Use The Following Testing Procedures
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65724)
Important: DO NOT replace the ECM, the fuel rail pressure regulator, or the fuel rail pressure sensor for this condition.

Wiring Harness Conditions
A secondary cause of DTC P0191 may result from a poor connection at the pigtail connector, or the engine harness connector, incorrect crimps, corrosion, and/or poor terminal tension.

1. Inspect the six-inch pigtail connector, which connects the FRP sensor to the main engine harness for incorrect crimps, corrosion, and/or poor terminal tension. Refer to Inline Harness Connector End Views for the appropriate model and year, and Circuit Testing and Wiring repairs in SI.
2. Inspect the Engine Chassis Harness to Engine Harness connector for incorrect crimps, corrosion, and/or poor terminal tension. Refer to Inline Harness Connector End Views for the appropriate model and year, and Circuit Testing and Wiring Repairs in SI.
Voltage Fluctuations/Interruptions at Key Up
Voltage fluctuations at key up, which false trigger a DTC P0191 can be very brief (less than 1 second) and may occur due to any aftermarket equipment installed on the vehicle.
Important: Aftermarket electrical equipment should have a diode connected across the power circuit (coil side) of the relay or solenoid being used in order to prevent transient voltage spikes. For more information on this subject, refer to Corporate Bulletin Number 08-08-45-004A.

Inspect for the proper installation and operation of any aftermarket equipment that may interrupt/interfere with the ignition voltage to the ECM. Refer to Checking Aftermarket Accessories in SI.
The following list is an indication of some of the types of aftermarket equipment that upfitters install.
• Theft deterrent systems
• Relays or solenoids to operate the electrical system of a snow plow or salt spreader
• Handicap ramp safety interlock systems
• Internal and external communication and lighting systems
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65724)<a href="http://gsi.xw.gm.com...rom=sm#N65824">; (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65824%22%3E)

I would get some techron injector cleaner. keep fuel above 1/3 tank level. make sure the battery/alternator/connections are clean and secure.

THIS is the TSB about this very common problem .................


Subject: Malfunction Indicator Lamp (MIL) Illuminated, Intermittent DTC P0191, Slow Fuel Rail Pressure (FRP) Decay, Wiring Harness Connections, Voltage Fluctuations/Interruptions (Follow Correction Information Below)

Models: 2006–2009 Chevrolet Express, Kodiak, Silverado
2006–2009 GMC Savana, Sierra, TopKick
Equipped With Duramax™ Diesel Engine (RPOs LLY, LBZ, LMM)
Please Refer to GMVIS
This bulletin is being revised to update the reprogramming emission controller warranty coverage period information. Please discard Corporate Bulletin Number 09-06-04-022A (Section 06 — Engine/Propulsion System).
Condition
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65566)

Some customers may comment that the malfunction indicator lamp (MIL) is illuminated, or it illuminates intermittently.
The technician may find DTC P0191 set as current or in history. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65566)
Causes
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65578)

• A slow fuel rail pressure (FRP) decay rate may exist, due to an accumulated but harmless varnish buildup on the fuel injectors.
• The wiring harness connections may exhibit incorrect crimping, corrosion or poor terminal tension.
• Aftermarket electrical equipment may be improperly installed on the vehicle resulting in an interruption or fluctuation in voltage to the engine control module (ECM).
• The ECM monitors the FRP sensor voltage signal at engine start up. If the voltage signal is greater than (high fuel rail pressure) a calibrated amount DTC P0191 can set.
• The ECM monitors the FRP sensor voltage signal at engine shut down , expecting a decrease to a low voltage signal (low fuel rail pressure) within a calibrated amount of time. If the voltage signal is greater than a specified value within that specific time period, DTC P0191 can set.
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65578)
Correction
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65626)

Verify the model year of the vehicle in order to determine which one or both of the following procedures to utilize. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65626)
For 2006-2008 Vehicles – Diagnose Possible Slow Fuel Rail Pressure Decay First
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65639)
Important: DO NOT replace the ECM, the fuel rail pressure regulator, or the fuel rail pressure sensor for this condition.

1. Start and idle the engine.
2. Observe the Fuel Rail Pressure Sensor parameter with a scan tool. The parameter should be between 30-40 MPa, depending on engine coolant temperature (ECT).
3. Turn OFF the engine, and immediately turn the key to the ON position.
4. Using a stopwatch, observe the decay of the Fuel Rail Pressure Sensor parameter with a scan tool.
5. The Fuel Rail Pressure Sensor parameter should decay to less than 6.6 MPa within 15 seconds.
If the Fuel Rail Pressure Sensor parameter is more than the specified value within the specified time period, then reprogram the ECM.
Important: If a 2006-2007 LLY, LBZ vehicle has, as one of nine ECM module ID Part Numbers, Part Number 12632483, then reprogramming the ECM will not repair this condition. If a 2007i-2008 LMM vehicle had field action V1819 - 08142 ECM EEPROM - REPROGRAM ECM applied, then reprogramming the ECM will not repair this condition. All 2009 LMM's already have an extended rail pressure bleed down calibration.

A revised software calibration has been released to address this condition. Reprogram the ECM using the Service Programming System (SPS) with the latest calibration available on TIS2WEB. Refer to the SPS procedures in SI.
When using a multiple diagnostic interface (MDI) for reprogramming, ensure that it is updated with the latest software version.
When using a Tech 2® for reprogramming, ensure that it is updated with the latest software version.
During programming, the battery voltage must be maintained within the proper range of 12-15 Volts. Only use the approved Midtronics® PSC 550 Battery Maintainer (SPS Programming Support Tool EL-49642) or equivalent during programming. (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65639)
For 2006-2009 Vehicles – Use The Following Testing Procedures
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65724)
Important: DO NOT replace the ECM, the fuel rail pressure regulator, or the fuel rail pressure sensor for this condition.

Wiring Harness Conditions
A secondary cause of DTC P0191 may result from a poor connection at the pigtail connector, or the engine harness connector, incorrect crimps, corrosion, and/or poor terminal tension.

1. Inspect the six-inch pigtail connector, which connects the FRP sensor to the main engine harness for incorrect crimps, corrosion, and/or poor terminal tension. Refer to Inline Harness Connector End Views for the appropriate model and year, and Circuit Testing and Wiring repairs in SI.
2. Inspect the Engine Chassis Harness to Engine Harness connector for incorrect crimps, corrosion, and/or poor terminal tension. Refer to Inline Harness Connector End Views for the appropriate model and year, and Circuit Testing and Wiring Repairs in SI.
Voltage Fluctuations/Interruptions at Key Up
Voltage fluctuations at key up, which false trigger a DTC P0191 can be very brief (less than 1 second) and may occur due to any aftermarket equipment installed on the vehicle.
Important: Aftermarket electrical equipment should have a diode connected across the power circuit (coil side) of the relay or solenoid being used in order to prevent transient voltage spikes. For more information on this subject, refer to Corporate Bulletin Number 08-08-45-004A.

Inspect for the proper installation and operation of any aftermarket equipment that may interrupt/interfere with the ignition voltage to the ECM. Refer to Checking Aftermarket Accessories in SI.
The following list is an indication of some of the types of aftermarket equipment that upfitters install.
• Theft deterrent systems
• Relays or solenoids to operate the electrical system of a snow plow or salt spreader
• Handicap ramp safety interlock systems
• Internal and external communication and lighting systems
(http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65724)<a href="http://gsi.xw.gm.com...rom=sm#N65824">; (http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2390143&from=sm#N65824%22%3E)

I would get some techron injector cleaner. keep fuel above 1/3 tank level. make sure the battery/alternator/connections are clean and secure.

Thanks I've forward this to friend that is now working on issue.

Truck not stalling or hard to start. Actually seems to run fine, little hard of mpg 15.4... Getting scan tomorrow at my work. Will post what shows up.

that vehicle should get 18 MPG highway @70 MPH. at least. 87 octane fuel. normal load ..

I get on my 2000 1500 4X4 5.3L 18-19 mpg in the warm weather about 17 MPG in cold winter temps below 40 deg F.