What it means
Same as P233A but with the control line shorted to supply - the ECU measures a high voltage that does not match the commanded duty cycle.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Fuel pressure regulator C is controlled through an electrical circuit that lets the engine control module adjust fuel pressure. The module compares the circuit signal with the commanded duty cycle and sets P233C when it detects a signal higher than expected, such as from a short to a power supply.
Common causes
Most likely first.
- Control line shorted to battery or supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
How to diagnose it
- Record freeze-frame data and compare regulator C command with its circuit reading in live data to see when the high signal occurs.
- With the ignition off, inspect regulator C's connector and harness for corrosion, damaged insulation, or a wire pinched against a power feed.
- Check the connector terminals for corrosion, looseness, or poor contact that could distort the control signal.
- With the circuit isolated as specified by the manufacturer, check for an unintended connection between the regulator C control wire and battery or other supply voltage.
- If wiring checks pass, test the regulator C control circuit and regulator operation against the manufacturer's specifications.
Common fixes
- Repair chafed regulator C wiring that is contacting a power supply.
- Clean or repair corroded or damaged regulator C connector terminals.
- Repair a short to supply in the regulator C control circuit.
- Replace the regulator C solenoid only if circuit tests identify it as faulty.
Can I keep driving?
Avoid heavy acceleration and high engine loads because incorrect fuel pressure can cause stalling or power loss. If it stalls, becomes difficult to start, or loses power, stop driving and arrange a safe inspection.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.