P0233 – Fuel Pump Secondary Circuit Intermittent

P0233 is an OBD-II trouble code that points to an electrical problem in your fuel pump circuit, not the pump itself spinning or making noise. When this code sets, your engine computer (ECU/PCM) is seeing an intermittent or incorrect signal on the “Fuel Pump Secondary Circuit.” That can lead to stalling, hard starting, or a no-start situation. If you’ve scanned your car and found P0233, you’re smart to look into it quickly. This guide walks you through what it means, common causes, symptoms, diagnosis, and typical repair options.

What Does P0233 Mean?

P0233 stands for “Fuel Pump Secondary Circuit Intermittent.” In simple terms, the ECU is detecting an unstable or out-of-range voltage signal in the control or feedback side of the fuel pump circuit. It’s not just checking whether the pump has power; it’s watching the quality and consistency of that signal.

On many vehicles, the fuel pump is controlled through a relay or fuel pump control module. When the wiring, relay contacts, or module output become loose, corroded, or damaged, the ECU sees intermittent voltage or feedback and stores P0233. Left alone, this can progress from an occasional stumble to a complete no-start.

Quick Reference

• Code: P0233
• Definition: Fuel Pump Secondary Circuit Intermittent
• System: Fuel delivery / electrical
• Severity: Moderate to high (possible no-start)
• Typical causes: Relay, wiring, connectors, control module

Real-World Example / Field Notes

In the shop, I often see P0233 on vehicles that come in with a “sometimes it starts, sometimes it doesn’t” complaint. One common scenario: the car cranks for a long time in the morning, then suddenly fires up and runs fine all day. Scan shows P0233 stored, maybe with a history misfire code. A quick tap on the fuel pump relay or wiggle of the harness near the under-hood fuse box makes the pump cut in and out. Replacing a heat-soaked relay and repairing a slightly corroded connector usually fixes it for good. The key is catching the intermittent fault while it’s acting up.

Symptoms of P0233

• Hard starting – Long crank time before the engine finally starts, especially when hot or after sitting.
• No-start condition – Engine cranks but will not fire because the fuel pump isn’t running consistently.
• Intermittent stalling – Engine may stall at idle or while driving if the fuel pump loses power momentarily.
• Hesitation or stumble – Brief loss of power or surging as fuel pressure drops and recovers.
• Check engine light on – MIL illuminated, sometimes with other fuel or misfire codes stored.
• Reduced power – Weak acceleration if the fuel pump isn’t supplying steady pressure.
• Fuel pump noise changes – Pump may sound like it cuts in and out, or is quieter than usual when the key is turned on.

Common Causes of P0233

Most Common Causes

• Faulty fuel pump relay – Burned, pitted, or heat-soaked relay contacts can cause intermittent power to the pump or feedback circuit.
• Loose or corroded connectors – Connectors at the fuel pump, fuel pump module, or under-hood fuse/relay box often corrode or loosen, breaking the circuit intermittently.
• Damaged wiring harness – Chafed, pinched, or broken wires between the ECU, relay, and fuel pump can cause voltage drops or open circuits.
• Failing fuel pump control module – On vehicles that use a separate control module, internal faults can cause erratic output and trigger P0233.
• Poor ground connection – Rusted or loose ground points for the fuel pump or module can mimic a bad pump or relay.

Less Common Causes

• Internal fuel pump issues – The pump itself may have internal electrical faults or intermittent open windings, not just mechanical wear.
• ECU/PCM driver fault – Rare, but a failing ECU output driver can send unstable voltage to the relay or module.
• Aftermarket alarm or remote start wiring – Poorly installed theft-deterrent or remote start systems spliced into the fuel pump circuit can cause intermittent power loss.
• Water intrusion in fuse box – Moisture in the under-hood fuse/relay panel can corrode terminals and cause intermittent contact.
• Previous collision or repair damage – Body or frame repairs near the fuel tank or harness routing can pinch or misroute wiring.

Diagnosis: Step-by-Step Guide

You’ll want a basic scan tool, a digital multimeter (DMM), and ideally a wiring diagram for your specific vehicle. A test light and back-probing pins are helpful. If you have an advanced scan tool, Mode $06 and live data for fuel pump command/feedback can speed things up.

1. Verify the complaint and code – Confirm P0233 is present (current or history). Note any other codes, especially fuel pressure or misfire codes. Try to reproduce the symptom (hard start, stall, etc.).
2. Listen for the fuel pump – With key ON (engine off), listen near the tank for a 2–3 second pump prime. If it’s intermittent or silent, that supports a circuit issue.
3. Check fuses and relay – Locate the fuel pump fuse and relay. Inspect for heat damage or corrosion. Swap the relay with a known-good identical relay if available as a quick test.
4. Inspect wiring and connectors – Visually inspect harnesses from the fuse/relay box to the rear of the vehicle. Look for rubbed-through insulation, sharp bends, or previous repair splices. Unplug and inspect connectors for green corrosion or loose pins.
5. Test power and ground at the pump – With the connector at the fuel pump or fuel pump control module unplugged, use a DMM to check for proper battery voltage on the power wire and a solid ground when the pump is commanded on.
6. Wiggle test the harness – While monitoring voltage or pump operation, gently move sections of the harness and connectors. If the pump cuts in/out or voltage jumps, you’ve likely found the intermittent area.
7. Check relay control and feedback circuits – Using the wiring diagram, verify that the ECU is sending a proper control signal to the relay or module and that any feedback wire back to the ECU is stable.
8. Evaluate the fuel pump control module (if equipped) – Confirm power, ground, and command signal to the module. If input is good but output to the pump is intermittent, suspect the module.
9. Scan tool data review – On some vehicles, you can monitor fuel pump command, duty cycle, or fuel pressure data. Look for sudden drops or spikes that match the symptom.
10. Clear codes and road test – After repairs or adjustments, clear P0233 and perform a road test under similar conditions. Re-scan to confirm the code does not return.

Pro tip: Intermittent electrical problems often show up more when components are hot. If everything checks out cold, try lightly tapping the relay or module and gently heating the area with a heat gun (carefully) to reproduce the fault.

Possible Fixes & Repair Costs

Repairs for P0233 focus on restoring a clean, stable electrical path to the fuel pump. Depending on what you find, the fix can be simple or more involved.

• Replace fuel pump relay – Quick and common fix; parts usually $20–$60, labor minimal.
• Repair or replace connectors – Cleaning corrosion, tightening terminals, or installing new pigtails; typically $75–$250 depending on access.
• Wiring harness repair – Splicing in new wire sections or rerouting damaged harness; can range from $150–$500+ depending on length and location.
• Replace fuel pump control module – On vehicles that use one, parts often $150–$400, labor $100–$250.
• Replace fuel pump assembly – If the pump itself is intermittently failing, expect $300–$900+ parts and labor depending on vehicle and tank access.

Typical repair costs for P0233 run from about $150 for a simple relay and connector fix up to $800 or more if a pump and module are both needed. Labor rates in your area, how hard the fuel tank is to access, and whether wiring harness sections must be replaced all affect the final price.

Can I Still Drive With P0233?

In many cases, you can still drive with P0233 for a short period, but it’s risky. Because this code points to an intermittent fuel pump circuit, your car might run perfectly one moment and then stall or refuse to start the next. That’s not something you want to experience in heavy traffic or far from home. If the engine is running poorly, stalling, or taking a long time to start, plan repairs as soon as possible and avoid long trips until it’s fixed.

What Happens If You Ignore P0233?

If you ignore P0233, the intermittent issue usually gets worse. What starts as an occasional hard start can turn into frequent stalling or a complete no-start, leaving you stranded. Repeated low or unstable fuel pressure can also stress the fuel pump and other components. Addressing the electrical problem early is almost always cheaper than waiting until the pump and wiring are both damaged.

Last updated: January 22, 2026

Vehicles Commonly Affected by P0233

P0233 can show up on almost any OBD-II vehicle, but it’s more common on certain platforms that rely heavily on fuel pump control modules and complex relay circuits. You’ll often see this code on Ford and Lincoln trucks and SUVs (F-150, Expedition, Explorer), GM vehicles such as Chevrolet Silverado, Tahoe, and GMC Sierra, and various Dodge/Ram pickups and Chrysler/Jeep SUVs. Some European models from Volkswagen, Audi, and BMW that use sophisticated fuel delivery control can also log P0233 when wiring or module issues develop. High-mileage vehicles and those exposed to rust, road salt, or previous wiring work are especially prone.