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DTC P0191 on 2005 Ford E350 Motorhome: Causes, Fixes, and Can You Drive It?

Model: 2005 E350 Motorhome Fault Code: P0191 Posted: 2019-08-05 14:34

I recently purchased a 2005 Ford E350 chassis motorhome in excellent condition with only 30,000 miles. The vehicle runs smoothly, but it consistently shows DTC P0191 — Fuel Rail Pressure Sensor Circuit Malfunction. I replaced the Fuel Rail Pressure Sensor (FRPS) with a Bosch unit and cleaned all electrical contacts and ground connections as recommended. After resetting the code, the issue returned after approximately 30 miles of driving. I then replaced the Fuel Pump Drive Module and fuel filter, but the DTC P0191 reappeared shortly after. I also replaced the fuel pump relay under the hood with no improvement. When reviewing the 'Freeze Frame' data from my OBD2 scanner, fuel pressure readings appeared normal — showing around 45 psi at cruising speed (65 mph), 51 psi at idle, and rising to over 70 psi when exiting highways. I am considering replacing the fuel pump but have hesitated due to the tank being surrounded by sharp sheet metal and heat shields, which could damage fuel lines during removal. Is it safe to continue driving this vehicle while ignoring the P0191 code? Key technical details: - Vehicle: 2005 Ford E350 Class C Motorhome (V10 diesel) - DTC: P0191 - Fuel pressure readings appear within expected range - All major fuel system components have been replaced or serviced

Related fault codes
P0191
Comments (7)
Anonymous 2019-08-06 12:06

When replacing the FRPS, I cleaned all electrical contacts and grounds. To verify circuit integrity, test power, ground, and signal continuity. Refer to bbbind.com for a detailed wiring diagram. FordTechMakuloco.com offers comprehensive guides on diagnosing P0191.

Anonymous 2020-10-22 16:01

I have the same issue on my 2004 Class C E350 V10. The P0191 code appeared about five years ago. I've replaced the FRPS, fuel pump drive module twice, and the fuel filter. My RV now has over 100,000 miles and runs fine despite the check engine light being on. Before installing a new fuel pump, I had an electric fuel gauge added and noticed fuel pressure rising above 70 psi when exiting highways — about 45 psi at 65 mph cruising and 51 psi at idle. Did you install a new fuel pump?

Anonymous 2020-10-23 20:49

Could there be a fuel pressure regulator inside the tank, part of the fuel pump assembly? Is it possible to repair this regulation without replacing the entire fuel pump unit? (Jacques, 2004 Regency)

Anonymous 2020-11-18 13:21

I've had P0191 on my 2004 RV since 2015. At that time, I replaced coil pack #1. Could a faulty coil pack have caused issues with the PCM? Is it possible that a defective PCM is responsible for the P0191 code?

Anonymous 2020-11-19 10:26

A faulty coil pack would not cause a P0191 fault. Potential causes of DTC P0191 include: high or low fuel pressure, damaged FRP sensor, excessive circuit resistance, vacuum leaks, or lack of fuel supply. See more at fordtechmakuloco.com and viewtopic.php?t=18521 for detailed troubleshooting steps.

Anonymous 2020-11-21 17:19

I'm considering replacing the PCM as my last option — it's a significant expense. However, I've been driving this RV flawlessly for years. Could a faulty coil pack five years ago have caused an early failure in the PCM? I’m asking if there’s a historical link between these components.

Anonymous 2020-11-22 10:59

If all diagnostic tests pass and the P0191 code persists, it is most likely due to a failing PCM. Before replacing the PCM, perform a hard reset by disconnecting the battery for at least 30 minutes. Also consider replacing the FRP sensor — especially on diesel engines with common rail systems. CAUTION: Improper handling of fuel rail sensors can lead to system damage. See more details at p0191.