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DTC codes / P23xx · Ignition system and misfire / P233A

P233AFuel Pressure Regulator C Control Circuit Open

P233A indicates that the powertrain control module (PCM) has detected an open circuit in the control wiring for fuel pressure regulator C, which is typically a solenoid or electronic actuator used to manage fuel pressure. The PCM commands a specific pressure, but the electrical path to the regulator is broken, so the regulator cannot receive the command signal.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle or stumbling during acceleration due to incorrect fuel pressure
  • Reduced engine power or limp mode in some vehicles
  • Poor fuel economy or rich/lean fuel mixture symptoms
  • Hard starting or extended cranking time
  • Possible fuel odor or other driveability complaints

Common causes, most likely first

  1. Broken, chafed, or disconnected wire in the control circuit to the fuel pressure regulator
  2. Corroded or loose electrical connector at the regulator or PCM
  3. Failed fuel pressure regulator solenoid (open internal coil)
  4. Open circuit inside the PCM driver for that regulator circuit
  5. Rodent damage to wiring harness
  6. Aftermarket alarm or remote start installation interfering with wiring

How to diagnose and fix it

  1. Verify the code with a scan tool and check for related codes in other modules
  2. Inspect the wiring harness and connector at the fuel pressure regulator for damage or corrosion
  3. Measure resistance of the regulator solenoid with a multimeter and compare to specification
  4. Check for continuity and voltage drop on the control circuit between the PCM and regulator
  5. Test the PCM output with a noid light or oscilloscope if the circuit tests good
  6. Repair or replace damaged wiring, connector pins, or the regulator as needed
  7. Clear codes and perform a road test to confirm the repair

What the open circuit really tells you

  • An open circuit code does not always mean the regulator itself has failed; wiring and connector faults are equally common and should be ruled out first.
  • Some vehicles use a fuel pressure control module that can set this code when it fails, even though the regulator is fine.
  • A loose or corroded ground connection for the regulator circuit can mimic an open circuit and is often overlooked.
  • Aftermarket electrical accessories tapped into the harness near the fuel system can introduce opens or intermittent faults that set this code.
  • The PCM may set this code only after a specific number of key cycles, so a single clear may not immediately return the light.

Can I keep driving with P233A?

You can usually drive the vehicle to a repair shop, but avoid heavy acceleration or towing because fuel pressure may be incorrect and could cause driveability issues or catalyst damage. If the engine runs poorly or enters limp mode, stop driving and have it towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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