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P018C – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

P018C is an OBD-II Code that refers to Fuel Pressure Sensor B Circuit Low

Meaning

A P018C code is a diagnostic trouble code related to that occurs when the PCM/ECM detects an issue with the fuel level sensor B circuit. Pressure within the fuel rail varies constantly during normal driving. This is due to variations in fuel demand as a result of driving in varying conditions. The fuel pressure sensor is a component that converts the changes in pressure into a signal voltage, which is transmitted to the PCM right away. When the high or low fuel pressure is outside of normal range, the light may come on.

This DTC P018C will be set and stored when the Powertrain Control Module (PCM) detects a Fuel Pressure Sensor B Circuit Low Input condition. Once the PCM has detected the circuit low input, it will set the code and illuminate the MIL.

Causes

Common causes for this code include:

  • Malfunctioning fuel pressure sensor 
  • Fuel delivery problems 
  • Wiring or harness related issues
  • Bad PCM

Symptoms

The symptoms of a P018C code are:

Diagnosis

To diagnose a P018C DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the wiring and connectors involved in the circuit
  3. Test the reference voltage to the fuel pressure sensor with a multimeter
  4. Check for proper operation of the fuel pump relay 
  5. Check for proper operation of the fuel pump

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P018C code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the operation of the fuel pump relay and/or fuel pump.
  • Clearing the code before checking to see if it returns.

How serious is this?

A P018C code is a moderate to high severity code. It will cause the Check Engine Light to come on, and it can also cause issues with starting the engine, idling roughly, and stumbling or hesitating when trying to accelerate. If left unchecked, it could lead to more serious problems such as stalling.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Repair or replace any wiring that is damaged
  • Replace the fuel pressure sensor
  • Replace the fuel rail Pressure sensor
  • Replace the fuel pump relay
  • Install a new PCM if necessary 
  • Update the ECM software if needed

Related codes

A P018C is related to and may be accompanied by the following codes:

P0190 – Fuel Pressure Sensor A Circuit Malfunction

P2610 – ECM/PCM Internal Engine Off Timer Performance

P3009 – ECM/PCM Engine Speed Input Signal Missing or Improper

P061B – PCM Power Relay Sensing Circuit High Voltage

Conclusion

In conclusion, the P018C code is a diagnostic trouble code that refers to a problem with the fuel pressure sensor B circuit. This code is a moderate to high severity code that can cause starting, idling, and acceleration issues if left unchecked. The most common cause for this code is a malfunctioning fuel pressure sensor, but it can also be caused by fuel delivery problems or wiring and connector issues. To properly diagnose and fix the problem, a technician would need to inspect all the wiring and connectors involved in the circuit, test the reference voltage to the fuel pressure sensor, check for proper operation of the fuel pump relay, and check for proper operation of the fuel pump. In some cases, it may be necessary to install a new PCM or update the ECM software.