P0233: Fuel Pump Secondary Circuit Intermittent

The fuel pump circuit has two sides: the primary circuit is the engine module's output to the fuel pump relay coil (or to a pump control module), the secondary circuit is the power circuit from relay contact or module to the pump itself. P0233 reports brief, recurring dropouts in the pump power circuit that count neither as steadily low nor high. The secondary circuit is the power side of the same pump, not a second pump. No manufacturer using this code was found – GM counts intermittent faults within P0231/P0232/P023F, Ford's relay systems only use P0230–P0232; the description follows CARB's output monitoring requirement and Ford's description of the power circuit. Symptoms are occasional stumbling, stalling or starting problems.

Medium severity. Can I keep driving?Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

Symptoms

Occasional stumbling or jerking
Engine stalls now and then
Occasional starting problems
Check engine light on

Most likely causes

Loose contact at pump connector, tank flange or relay socket
Relay contacts burnt (intermittently high resistance)
Harness chafing at underbody or tank with intermittent contact
Pump motor with commutator or brush dropouts

What to check, in order

Start with the simplest. You can tick off each step.

Check the pump's fuse, relay, and connector
Gently move the wiring with the engine running and watch whether the reading changes.
Replace the filter if it is due for maintenance
Compare commanded and actual pressure in live data
Measure the pressure with a suitable gauge
Check the sensor and regulator before replacing the pump

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P0233 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
2: Fuel injection
33: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0233?

Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

What causes code P0233?

The most common causes are: loose contact at pump connector, tank flange or relay socket; relay contacts burnt (intermittently high resistance); harness chafing at underbody or tank with intermittent contact.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.