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P228C – 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

P228C is an OBD-II Code that refers to Fuel Pressure Regulator 1 Exceeded Control Limits – Pressure Too Low

Meaning

A P228C code is a general diagnostic trouble code that occurs when the PCM/ECM detects that the voltage in the regulator circuit is excessively below the normal parameter voltage. The Powertrain Control Module (PCM) uses sensor inputs to electronically control the fuel pressure regulator and in turn the control module makes some adjustments to the battery voltage and ground signal of the regulator while the vehicle is running.

A P228C code is set and stored when the PCM/ECM detects that the voltage regulator is not working properly and is not able to maintain the correct fuel pressure.

Causes

Common causes for this code include:

  • Shorted or open wiring and/or connectors in the fuel pressure regulator control circuit 
  • Engine timing problem
  • Faulty fuel pressure sensor 
  • Low engine oil pressure 
  • Bad fuel pressure regulator 
  • Bad or malfunctioned PCM/PCM

Symptoms

The symptoms of a P228C code are:

  • Illuminated Check Engine Light
  • Hard starting when cold
  • Increased exhaust emissions
  • Decreased fuel efficiency

Diagnosis

To diagnose a P228C DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect all wiring and connectors in the fuel pressure regulator control circuit for any signs of damage or corrosion.
  3. Check engine timing and adjust if necessary.
  4. Check engine oil pressure and add oil as needed.
  5. Test the fuel pressure sensor and replace if necessary.
  6. Test the fuel pressure regulator and replace if necessary.
  7. Replace the PCM/ECM if it is determined to be bad.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P228C code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the engine timing and adjusting if necessary.
  • Not checking the engine oil pressure and adding oil as needed.
  • Not testing the fuel pressure sensor and replacing it if necessary.
  • Not testing the fuel pressure regulator and replacing it if necessary.
  • Not replacing the PCM/ECM if it is determined to be bad.

How serious is this?

A P228C code is a serious code and should be addressed as soon as possible. If the code is not corrected, it may cause drivability problems and/or decreased fuel efficiency.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Repair or replace any wiring that is damaged
  • Replace the Pressure Fuel Pump harness
  • Replace the Pressure Fuel Pump
  • Replace the fuel pressure sensor
  • Replace the fuel pressure regulator
  • Replace the PCM/ECM

Related codes

A P228C is related to and may be accompanied by the following codes:

P0228 – Fuel Pressure Regulator 1 Control Circuit Low

P0229 – Fuel Pressure Regulator 1 Voltage Below Normal

Conclusion

In conclusion, the P228C code is a diagnostic trouble code that refers to a problem with the fuel pressure regulator. The code is set when the PCM/ECM detects that the voltage in the regulator circuit is excessively below the normal parameter voltage. The code may cause drivability problems and/or decreased fuel efficiency. The most common repairs for this code are to replace the wiring, the pressure fuel pump harness, the pressure fuel pump, and/or the fuel pressure sensor. If the PCM/ECM is determined to be bad, it should also be replaced.