P0233
Fuel Pump Secondary Circuit Intermittent
Intermittent fault on the secondary fuel pump circuit (transfer/lift pump or low-pressure stage). Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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
Common causes
Ordered by how often each turns out to be the cause.
- Connector loose or corrodedCommon
- Connector with intermittent contact under vibrationLess likely
- Harness routed against vibrating componentLess likely
Parts involved
- Secondary Fuel Pump
- Pump Wiring
P0233 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.