Good morning,
This sounds like a wiring issue. You could have corroded connections or a wire harness issue. You have replaced the components for the system but the controls could be the issue.
I attached some possibilities for you to view along with a flow chart. You will need a scan tool for some of the steps.
Roy
P0191
Descriptor
Probable Causes
Circuit Resistance High
Fuel Rail Pressure (FRP) Relay Sensor Damaged
High Fuel Pressure
Low Fuel Pressure
Low or No Fuel
Vacuum Leaks
WARNING: VEHICLE FUEL SYSTEMS ARE PRESSURIZED EVEN WHEN THE ENGINE IS NOT RUNNING. TO AVOID FIRE OR PERSONAL INJURY, DISABLE THE FUEL DELIVERY SYSTEM AND RELIEVE FUEL SYSTEM PRESSURE BEFORE REMOVING ANY FUEL SYSTEM COMPONENT. REFER TO THE FUEL SYSTEM INFORMATION AT THE BEGINNING OF PINPOINT HC. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
Note:With the engine running, the FRP PID value may be 48-70 kPa (7-10 psi) higher than a fuel pressure reading taken with a mechanical gauge.
This pinpoint test is intended to diagnose the following:
- fuel rail pressure (FRP) sensor (6B288)
- fuel rail temperature (FRT) sensor (4702)
- fuel rail pressure temperature (FRPT) sensor (9G756)
- harness circuits: FRP, FRT, and FRPT
- powertrain control module (PCM) (12A650)
Tables and Graphs
FRP SENSOR VOLTAGE AND PRESSURE SPECIFICATIONS
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FRT SENSOR TEMPERATURE, VOLTAGE, AND RESISTANCE SPECIFICATIONS
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Fuel Rail Pressure (FRP) Sensor Connector
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Fuel Rail Temperature (FRT) Sensor Connector
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Fuel Rail Pressure Temperature (FRPT) Sensor Connector
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Powertrain Control Module (PCM) Connector
For PCM connector views or reference values, refer to Section 6 See: Computers and Control Systems > Diagnostic Trouble Code Tests and Associated Procedures > SECTION 6: Reference Values.
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Images (Click to enlarge)
May 24, 2019 at 8:13 AM
