P0231
Fuel Pump Secondary Circuit Low
Fuel delivery
Generic OBD-II
High
What it means
P0231 means the voltage on the fuel-pump secondary (control) circuit is lower than expected. This circuit drives the fuel pump, so a fault here can reduce or cut off fuel delivery — leading to hard starting, stalling, or a no-start until the wiring, relay, or pump is repaired.
High
Can I keep driving? Risky — a failing fuel-pump circuit can starve the engine and cause stalling or a no-start, so plan to fix it before it strands you.
Common symptoms
What you'll notice
- Check-engine light on
- Hard starting, or a crank with no-start
- Engine starts then stalls, or stalls under load
- Poor performance and hesitation
Common causes
Most likely first
- Faulty fuel-pump relayLikely
- Broken, shorted, or corroded wiring in the pump control (secondary) circuitCommon
- Poor ground or connector at the pump or relayCommon
- Failed fuel pump or pump driver moduleLess often
- PCM fuel-pump driver fault (less common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then check the fuel-pump fuse and relay first.
- Inspect the pump control wiring, grounds, and connectors for damage or corrosion.
- Measure control-circuit voltage and pump feed with the key on and while cranking.
- If the circuit is good but pressure is low, test the pump and its driver module. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0231?+
Not reliably. A weak or failing pump circuit can cut fuel delivery and leave you stranded. Address it promptly.
Can I just clear P0231?+
You can, but it returns as soon as the circuit fault recurs. This is an electrical fault, not something that clears itself.
Related codes
Often seen with P0231
Read & clear P0231 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX