Can you keep driving?
Can you keep driving?
Stop driving if any of these apply
- !The engine starts stalling, losing power sharply, or refusing to respond to throttle normally.
- !The check-engine light flashes or the vehicle suddenly runs much worse after the code appears.
What to check first
Step-by-step checks
- 1
Free - no tools
Check whether the engine stalls randomly, restarts after cooling, or loses fuel pressure under bumps or load
- 2
Free - no tools
Inspect the pump relay, fuse, connector, and harness for looseness or heat damage
- 3
Basic tool needed
If the vehicle has a pump module or controller, inspect that side of the circuit too
- 4
Basic tool needed
Use a wiggle test if safe and available to see whether the fault appears when the harness is moved
- 5
Basic tool needed
If the pump is noisy or intermittent, treat that as a meaningful clue rather than background noise
If the code returns
- -If the fault appears with harness movement, wiring repair should come before a new pump.
- -If the relay heat-soaks and then fails, that part rises on the list.
- -If the code returns after repair, recheck the connector fit and routing before assuming the new part failed.
Background
What this code means
P0233 is a generic OBD-II code for an intermittent fuel pump secondary circuit fault.
That often means the pump circuit works some of the time but drops out or becomes unstable under vibration, heat, or load.
Diagnosis
Common causes
Loose connector or pin fit
Intermittent contact can stop the pump circuit at random.
Failing relay or module
Heat or vibration can make a marginal part drop out.
Harness break or rub-through
Movement can open or short the circuit intermittently.
Pump-side connection issue
A poor connector at the pump can behave the same way.
Avoid these mistakes
What not to do
- xDo not replace the sensor or pump first if there is obvious wiring, connector, or intake damage.
- xDo not ignore drivability changes or stalling just because the code sounds electrical.
Parts
Parts that may need replacing
See also
Related OBD codes
Source notes
Generic OBD-II (SAE J1979 / ISO 15031-5). P0233 was expanded around intermittent fuel-pump secondary circuit faults, especially loose connectors, broken wiring, and heat-related failures.
This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.
This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.
Last reviewed: 2026-04-10
Reference: Open reference