AutoCodes – Generic – P1186

P1186 Code - Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low

Quick Answer

As input rail pressure sensor signal, the Engine Control Module (ECM) of the standard rail diesel engine controls Fuel Pressure Regulator Valve (integrated with a high-pressure pump) to maintain optimum rail pressure according to current engine rpm and load. Common causes include Faulty Fuel Pressure Regulator Valve (FPRV) stuck open, Faulty Fuel Rail Pressure Sensor (RPS), Fuel Rail Pressure Sensor 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: P1186 indicates Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low.
Common causes: Common causes include Faulty Fuel Pressure Regulator Valve (FPRV) stuck open, Faulty Fuel Rail Pressure Sensor (RPS), Fuel Rail Pressure Sensor 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 56,195

How popular is this code, among other codes? Medium

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 Apr 23, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1186 Description

As input rail pressure sensor signal, the Engine Control Module (ECM) of the standard rail diesel engine controls Fuel Pressure Regulator Valve (integrated with a high-pressure pump) to maintain optimum rail pressure according to current engine rpm and load. However, when the problem that leads rail pressure out of target value intended by ECM occurs due to mechanical or electrical reasons, ECM shuts the engine down and sets Diagnostic Trouble Code (DTC) by limiting the fuel (stopping injector operation) to prevent the engine from being controlled abnormally. "Rail Pressure Monitoring Error" is the DTC that diagnoses the following:
1. Supplying state of low-pressure fuel
2. Mechanical operating conditions of the high-pressure pump
3. Indirectly based on Rail Pressure Sensor (RPS) output voltage and RPS duty.

OBDII Code P1186 - Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low - AutoCodes.com — P1186 Code - Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low

What does this mean?

What are the Possible Causes of the DTC P1186?

Faulty Fuel Pressure Regulator Valve (FPRV) stuck open
Faulty Fuel Rail Pressure Sensor (RPS)
Fuel Rail Pressure Sensor harness is open or shorted
Fuel Rail Pressure Sensor circuit poor electrical connection

How to Fix the DTC P1186?

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 P1186 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.

Need more information about the P1186 code?

Need more information on how to fix the P1186 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1186 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1186 Audi — Linear Oxygen Sensor Common Ground Short To Positive
P1186 BMW — O2 Sensor Heater Control Circuit Bank 1 Sensor 2
P1186 Buick — Engine Oil Temperature Sensor Circuit Performance
P1186 Cadillac — Engine Oil Temperature Sensor Circuit Performance
P1186 Chevrolet — Engine Oil Temperature Sensor Circuit Performance
P1186 Ford — Fuel Pump Temperature Sensor Low
P1186 GMC — Engine Oil Temperature Sensor Circuit Performance
P1186 Hyundai — Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low
P1186 KIA — Fuel Pressure Monitoring-Minimum Pressure at Engine Speed Too Low
P1186 MINI — O2 Sensor Heater Control Circuit Bank 1 Sensor 2
P1186 Volkswagen — Linear Oxygen Sensor Common Ground Short To Positive

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 P1186 Code

1. What are the common symptoms of OBDII code P1186?

- Common symptoms of code P1186 include reduced engine performance, rough idling, stalling, and difficulty starting the vehicle.

2. What are the possible causes of OBDII code P1186?

- Possible causes of code P1186 include a faulty fuel pressure regulator, clogged fuel filter, weak fuel pump, fuel system leaks, or issues with the fuel pressure sensor.

3. How can I diagnose the root cause of OBDII code P1186?

- Diagnosing code P1186 involves checking the fuel pressure using a gauge, inspecting the fuel pressure regulator, fuel filter, fuel pump, and fuel lines for any issues, and testing the fuel pressure sensor for proper functionality.

4. Can I still drive my vehicle with OBDII code P1186?

- It is not recommended to drive your vehicle with OBDII code P1186, as it can lead to further damage to the engine and potentially unsafe driving conditions.

5. How can I repair OBDII code P1186?

- Repairing code P1186 involves addressing the root cause of the issue, which may include replacing the fuel pressure regulator, fuel filter, fuel pump, or repairing any fuel system leaks. It is recommended to consult a professional mechanic for a proper repair.

6. Is it safe to reset the OBDII code P1186 and continue driving?

- Resetting the code without addressing the underlying issue is not recommended, as the problem may persist and potentially cause more severe engine damage. It is best to diagnose and repair the root cause of the code before driving the vehicle.

7. Can a dirty fuel injector cause OBDII code P1186?

- While a dirty fuel injector may not directly cause OBDII code P1186, it can contribute to fuel delivery issues that may lead to low fuel pressure, which can trigger the code.

8. Will using a fuel system cleaner help resolve OBDII code P1186?

- Using a fuel system cleaner may help improve fuel system performance, but it is unlikely to resolve OBDII code P1186 if the issue is related to a faulty component such as the fuel pressure regulator or fuel pump.

9. How often should the fuel pressure system be inspected to prevent OBDII code P1186?

- It is recommended to have the fuel pressure system inspected as part of regular maintenance, especially if you notice any symptoms of low fuel pressure. Regular inspections can help prevent issues that may trigger code P1186.

10. Can extreme weather conditions affect the fuel pressure system and trigger OBDII code P1186?

- Extreme weather conditions, such as extreme heat or cold, can affect the fuel pressure system and may contribute to issues that trigger code P1186. It is important to monitor your vehicle's performance in varying weather conditions and address any abnormalities promptly.