AutoCodes – RAM – P0191 RAM

P0191 RAM Code - Fuel Rail Pressure Sensor Circuit Range/Performance

Quick Answer

This Diagnostic Trouble Code (DTC) is mapped to an idle diagnostic and runs only at idle. Common causes include Low or no fuel, Faulty Fuel Rail Pressure (FRP) Sensor, Fuel Rail Pressure harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0191 RAM indicates Fuel Rail Pressure Sensor Circuit Range/Performance.
Common causes: Common causes include Low or no fuel, Faulty Fuel Rail Pressure (FRP) Sensor, Fuel Rail Pressure harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 528

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 04, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0191 RAM Description

This Diagnostic Trouble Code (DTC) is mapped to an idle diagnostic and runs only at idle. The key-on error monitors fuel pressure voltage at key-on after an eight-hour cold soak. The Powertrain Control Module (PCM) varies fuel pressure and monitors the final fueling and engine speed to determine if the rate of change of fueling with respect to the rate of change of pressure is within the normal operation limits of the pressure sensor. The engine must be at operating temperature and must not be in an active aftertreatment regeneration mode in order to run this diagnostic. The idle monitor runs once per drive cycle and the PCM will light the MIL lamp after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles. The DTC will be set when at idle, the rate of change in fueling with respect to the rate of change of pressure is below the calibrated fail high threshold or above the calibrated fail low threshold while the monitor was running.

OBDII Code P0191 RAM - Fuel Rail Pressure Sensor Circuit Range/Performance - AutoCodes.com — P0191 RAM Code - Fuel Rail Pressure Sensor Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P0191 RAM?

Low or no fuel
Faulty Fuel Rail Pressure (FRP) Sensor
Fuel Rail Pressure harness is open or shorted
Fuel Rail Pressure circuit poor electrical connection
Faulty Fuel Pump

How to Fix the DTC P0191 RAM?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0191 RAM code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0191 RAM Code

1. What are the common symptoms of OBDII code P0191?

- Common symptoms include rough idling, loss of power, engine stalling, poor fuel efficiency, and the illumination of the Check Engine Light.

2. What are the typical causes of OBDII code P0191?

- The code P0191 is often caused by a faulty fuel rail pressure sensor, issues with the fuel pump, problems with the fuel pressure regulator, or wiring/connectivity issues.

3. How can I diagnose OBDII code P0191?

- Diagnosis involves using an OBDII scanner to retrieve the code, inspecting the fuel rail pressure sensor and related components for damage, checking fuel pressure levels, and performing a thorough visual inspection of wiring and connections.

4. Can I drive with OBDII code P0191?

- It's not recommended to drive with this code as it can lead to more severe engine problems and potential safety hazards. It's best to address the issue promptly.

5. How is OBDII code P0191 repaired?

- Repairing the code typically involves replacing the faulty fuel rail pressure sensor, repairing/replacing damaged wiring or connectors, ensuring proper fuel pressure, and clearing the code using an OBDII scanner.

6. Are there any DIY tips for fixing OBDII code P0191?

- While some basic checks like inspecting wiring connections can be done by DIY enthusiasts, it's recommended to have a professional mechanic diagnose and repair this code due to the complexity of the fuel system.

7. Can a dirty fuel filter cause OBDII code P0191?

- Yes, a clogged or dirty fuel filter can restrict fuel flow and lead to abnormal fuel pressure readings, potentially triggering the P0191 code. It's advisable to inspect and replace the fuel filter if necessary.

8. How long does it take to repair OBDII code P0191?

- The repair time for OBDII code P0191 can vary depending on the exact cause of the issue, but it typically takes a few hours to diagnose and fix the problem, including sensor replacement and testing.

9. Will resetting the Check Engine Light resolve OBDII code P0191?

- Simply resetting the Check Engine Light without addressing the underlying issue will not resolve OBDII code P0191. It's crucial to diagnose the problem, fix the root cause, and then clear the code.

10. Is OBDII code P0191 a serious issue?

- While the severity of the issue may vary, ignoring OBDII code P0191 can lead to potential engine damage, decreased fuel efficiency, and unsafe driving conditions. It's best to address the problem promptly.