OBD-II trouble code
P0232: Fuel Pump Secondary Circuit High
The engine computer saw battery voltage on the fuel pump power feed when the pump should have been off. Usually a stuck-closed relay or a wire shorted to power, which can leave the pump running with the key off.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air Metering
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $40 – $900
- DIY difficulty
- Intermediate DIY
What does P0232 mean?
The secondary circuit is the high-current feed that carries battery voltage from the fuel pump relay or pump control module to the pump motor in the tank. The engine control module watches the voltage on that feed and expects it to follow its own commands: near battery voltage when the pump is commanded on, and near zero when it is commanded off.
P0232 is the opposite of P0231. It sets when the computer commands the pump OFF but still senses voltage on the feed. The circuit is being fed from somewhere it should not be. The two usual explanations are a relay whose contacts have welded closed from arcing, or a chafed feed wire that has rubbed through and touched a permanently hot wire or a hot terminal in a fuse box.
The practical consequence is a fuel pump that never shuts off. That is a safety concern rather than a driveability one. A pump running continuously with the engine off will drain the battery over a few hours, and — more seriously — in a collision the inertia or ECM shutoff that is supposed to kill the pump may not work, so fuel keeps being pumped from a possibly ruptured line. Some vehicles also over-pressurize the fuel rail, causing a rich-running condition, hard hot starts, and fuel-fouled plugs. Do not drive with P0232 stored; get the circuit repaired first.
Common causes
- Fuel pump relay with welded or stuck-closed contacts
- Fuel pump feed wire chafed and shorted to a constant battery-voltage wire
- Damage or corrosion inside the underhood fuse box bridging adjacent terminals
- Failed fuel pump driver/control module stuck in the on state
- Aftermarket wiring, an alarm install, or a previous repair back-feeding the pump circuit
- Water intrusion into a connector creating a leakage path to a hot terminal
- Rarely, an internally failed ECM/PCM output driver
Symptoms
- Fuel pump audibly runs continuously, including with the key off
- Battery drains overnight or over a few hours
- Rich running, black smoke, or a strong fuel smell in some cases
- Hard starting when the engine is hot
- Check engine light on
- Fuel pressure higher than specification or slow to bleed down after shutdown
Diagnostic steps
- 1.Confirm P0232 and note whether P0230 or P0231 is also present, which changes where in the circuit to look.
- 2.Turn the key off, wait for the normal prime cycle to end, and listen at the fuel filler. A pump still humming confirms the circuit is being fed with the pump commanded off.
- 3.Pull the fuel pump relay. If the pump stops, the relay contacts are welded or the ECM is holding it on — check the relay coil control leg with a meter to tell which.
- 4.If the pump keeps running with the relay removed, the feed wire is shorted to a hot source. Disconnect the battery and check the feed wire for continuity to any constant-voltage circuit.
- 5.Inspect the underhood fuse box for corrosion, water intrusion, melted plastic, or terminals bridged by debris.
- 6.Trace the pump feed wire along the frame rail and floor pan looking for chafe points, especially near clips, brackets, and previous repair splices.
- 7.If the relay, wiring, and fuse box all test good, suspect the fuel pump driver module or the ECM's internal driver.
Repair cost
$40 – $900
Replacing a stuck relay is often $15-$60 in parts and minutes of labor. Repairing a shorted or chafed feed wire typically runs $150-$450 depending on how much harness has to be traced and unwrapped. A damaged underhood fuse box is $150-$600. A fuel pump driver module is $150-$500 plus 0.5-1.5 hours. Diagnosis alone is usually $75-$150.
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 intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.