Code P0191

NICKP3750

MEMBER
2006 FORD ESCAPE
2.3L
4 CYL
4WD
AUTOMATIC
262,000 MILES

About a month ago, was driving and engine stalled. Started back up, but then stalled immediately after. Got it home, checked the code and it gave me P0191 Fuel Rail Pressure Sensor. Replaced the sensor, still had issues. So I replaced the fuel filter and fuel pump and got a more expensive sensor, ran fine after that. Two days ago, stalled again and spit the same code. Found out the fuel pump was an Airtech with a Delphi label on it, so replaced the fuel pump with a better one and replaced the sensor again with a Motorcraft. Still not starting up and when I plug in the code reader and switch to live data it is showing no fuel pressure when the key is turned over. Also not hearing the pump turn on when I turn the key over.

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

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

imageOpen In New TabZoom/Print

FRT SENSOR TEMPERATURE, VOLTAGE, AND RESISTANCE SPECIFICATIONS

imageOpen In New TabZoom/Print

Fuel Rail Pressure (FRP) Sensor Connector

imageOpen In New TabZoom/Print

image

Fuel Rail Temperature (FRT) Sensor Connector

imageOpen In New TabZoom/Print

image

Fuel Rail Pressure Temperature (FRPT) Sensor Connector

imageOpen In New TabZoom/Print

image

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.

ImageOpen In New TabZoom/Print

Images (Click to make bigger)