OBD-II trouble code
P0233: Fuel Pump Secondary Circuit Intermittent
The engine computer saw the fuel pump power feed drop out and recover. Nothing is wrong right now, but a loose connector, corroded terminal, or chafed wire is breaking the circuit intermittently — a classic cause of random stalling.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air Metering
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $40 – $1,200
- DIY difficulty
- Advanced DIY
What does P0233 mean?
P0233 is the intermittent member of the fuel pump secondary circuit family. The secondary circuit is the heavy power feed running from the fuel pump relay or pump control module to the pump motor in the tank. The engine control module monitors the voltage on that feed, and P0233 sets when the reading briefly goes out of range and then returns to normal on its own.
Because the fault comes and goes, the code rarely reflects a component that has completely failed. It reflects a connection that is marginal. Vibration, heat cycling, moisture, and road salt slowly degrade terminals and wire insulation, and the resulting connection works most of the time and drops out under the right conditions. The tank-top pump connector, the fuel pump relay socket, and any chafe point along the frame rail are the usual suspects.
The practical danger is the stall. When the feed drops out, the pump stops, fuel pressure collapses within seconds, and the engine quits — often at speed, often with no warning. It usually restarts once the connection remakes itself, which is exactly why intermittent faults get ignored until they strand someone. Take P0233 seriously and find the marginal connection rather than waiting for it to become permanent.
Common causes
- Corroded or heat-damaged terminals in the fuel pump module connector on top of the tank
- Loose, spread, or backed-out pins in the fuel pump relay socket
- Chafed pump feed wire intermittently grounding against the frame rail or floor pan
- Marginal fuel pump relay with pitted contacts that make and break under vibration
- Loose or corroded ground connection for the pump circuit
- Failing fuel pump motor with worn brushes that cut out when hot
- Water intrusion into a harness connector, worse in wet weather
Symptoms
- Random stalling with no warning, often followed by a successful restart
- Intermittent no-start or extended crank
- Momentary hesitation, surge, or stumble under load
- Fuel pump prime sound is inconsistent when the key is turned to ON
- Check engine light that comes on and later goes out
- Fuel pressure that drops out briefly when the harness is wiggled
Diagnostic steps
- 1.Confirm P0233 and check freeze frame data for the conditions when it set — road speed, engine load, and coolant temperature narrow down whether heat, vibration, or moisture is the trigger.
- 2.Inspect the fuel pump relay and its socket for pitted contacts, browned terminals, or spread pins; substitute a known-good relay of the same part number as a test.
- 3.Access the fuel pump module connector on top of the tank and inspect it closely for green corrosion, melted plastic, or pushed-back terminals — this is the single most common failure point.
- 4.Wiggle-test the pump harness and relay while monitoring fuel pressure or pump current on a scan tool or meter; a momentary dropout localizes the fault.
- 5.Trace the pump feed and ground wires along the frame rail and floor pan looking for chafe points, especially at clips, brackets, and prior repair splices.
- 6.Perform a voltage-drop test on both the power and ground legs with the pump running; more than about half a volt indicates a degraded connection even if it currently works.
- 7.Monitor fuel pump current draw with a clamp meter over a road test — erratic or spiking draw points at a failing pump motor rather than the wiring.
Repair cost
$40 – $1,200
Because the fault is intermittent, diagnostic time drives the bill — expect $100-$250 for the shop to find it. A relay is $15-$60. Repairing a corroded tank-top connector or splicing a chafed wire typically runs $150-$400. If the pump module itself is at fault, budget $120-$700 in parts plus 1.5-4 hours of labor depending on whether the tank must be dropped.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with check engine light diagnosis preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.