A fuel pump that keeps running when it should be off drains the battery and can be a safety concern. A P0232 code means the engine computer saw voltage on the fuel pump secondary circuit that was higher than expected, often when the pump should have been off.
This guide explains what puts unwanted voltage on the pump circuit, how to test it and which repairs fix it.
P0232 Code Breakdown
Every OBD-II code follows the same five-character pattern set by the SAE J2012 standard. Each character narrows down which system has the fault. This table shows what each part of the code tells you.
| Character | Meaning | What It Tells You |
|---|---|---|
| P | Powertrain | The fault is in the engine or transmission systems. |
| 0 | Generic (SAE) code | The definition is the same on every OBD-II vehicle. |
| 2 | Fuel and air metering | The fault involves fuel and air metering, such as injectors, the fuel pump, throttle sensors or boost control. |
| 32 | Specific fault | Fuel Pump Secondary Circuit High |
What the P0232 Code Means
The SAE J2012 standard defines the P0232 code as Fuel Pump Secondary Circuit High. Most fuel pumps are powered through a relay. The powertrain control module (PCM) switches the relay coil, which is the primary or control side of the circuit. The relay contacts then send battery power to the pump, which is the secondary or power side.
Many Ford, Lincoln and some other vehicles use a fuel pump driver module (FPDM) instead of a simple relay. The PCM tells the module how fast to run the pump, and the module powers it. On these vehicles, the module is often mounted on the frame or near the spare tire, where it is exposed to water and road salt.
The PCM watches the circuit it controls and, on many vehicles, a feedback wire from the pump side. When those voltages do not match its command, it sets a fuel pump circuit code.
This code points to the secondary side. The PCM expects the pump circuit voltage to drop when it turns the pump off. If voltage stays high, or rises above the expected value, the PCM decides the relay is stuck or the circuit is shorted to power.
Symptoms of a High Fuel Pump Circuit Voltage
Fuel delivery problems are hard to miss. Common signs of a P0232 code include:
- Fuel pump runs with the key off
- Dead battery after the car sits
- Fuel pump runs constantly with the key on
- Check engine light on
- Engine runs normally in many cases
Listen at the fuel tank after you turn the engine off. If the pump keeps humming, the relay or module is likely stuck on.
What Causes the P0232 Code?
These are the usual causes:
- Relay stuck closed. Welded contacts keep the pump powered.
- Pump power wire shorted to battery voltage. Damaged insulation touches a live wire.
- Faulty fuel pump driver module. An internal short keeps the output on.
- Wrong relay installed. A relay with a different pin layout can feed power the wrong way.
- PCM fault. Rare.
Tools You Will Need
You can do most of this testing at home with basic tools:
- OBD-II scan tool that can command the fuel pump
- Digital multimeter and test light
- Fuel pressure gauge for your fuel system
- Fused jumper wire
- Wiring diagram showing the relay or fuel pump driver module
How to Track Down the P0232 Code
Fuel pump circuits are simple, so a careful step-by-step check usually finds the fault quickly. Keep sparks and flames away from the fuel system while you test.
Listen for the Pump with the Key Off
Turn the engine off, remove the key and listen at the tank. A running pump confirms a stuck relay, a shorted module or a short to power.
Pull the Relay
Remove the fuel pump relay with the key off. If the pump stops, the relay is stuck closed. Replace it with the correct part number.
If the pump keeps running with the relay out, the pump power wire is shorted to another voltage source. Trace the wiring between the relay box and the tank.
Check the Driver Module
On vehicles with a fuel pump driver module, unplug the module with the key off. If the pump stops, the module is at fault. Check the module’s power and command wires before replacing it.
Check the Feedback Wire
Some PCMs read pump voltage through a separate feedback wire. A feedback wire shorted to power can set this code even when the pump works normally.
Repairs That Clear the P0232 Code
Match the repair to what your tests found. Then clear the code and drive under the same conditions that set it.
- Replace a stuck relay with the correct part number.
- Repair a short to voltage in the pump power wiring.
- Replace the fuel pump driver module if it keeps the pump on.
- Repair the feedback wire if it is shorted to power.
After the repair, turn the key on and off a few times. The pump should run for a couple of seconds at key on and then stop.
Common Mistakes to Avoid
These mistakes waste money or leave the real fault in place:
- Replacing the fuel pump before checking the relay, fuse and driver module
- Forgetting the inertia switch on vehicles that have one
- Jumping the relay socket with an unfused wire
- Ignoring corrosion on a frame-mounted fuel pump driver module
Repair Cost Breakdown
The cost to fix a P0232 code depends on the cause. This table shows typical ranges for parts and labor.
| Repair | DIY Cost | Typical Shop Cost |
|---|---|---|
| Fuse or relay | $5 to $40 | $50 to $150 |
| Wiring or connector repair | $10 to $50 | $100 to $350 |
| Fuel pump driver module | $60 to $250 | $200 to $500 |
| Fuel pump assembly | $100 to $500 | $400 to $1,200 |
Fuel pump replacement is the most expensive repair here, especially on vehicles where the tank must be dropped. A relay, fuse or driver module is far cheaper and causes many of these codes, so test them first.
Is It Safe to Drive with a P0232 Code?
It is usually drivable, since the pump still runs. But a pump that runs with the key off can drain the battery and leave you stranded.
A short to voltage can also blow fuses or damage wiring. Get it fixed soon, and pull the fuel pump fuse overnight if the pump will not stop.
Related Codes
These codes often show up with this one or point to the same system:
| Code | Meaning |
|---|---|
| P0230 | Fuel Pump Primary Circuit Malfunction |
| P0231 | Fuel Pump Secondary Circuit Low |
| P0233 | Fuel Pump Secondary Circuit Intermittent |
| P0087 | Fuel Rail/System Pressure Too Low |
| P0627 | Fuel Pump A Control Circuit/Open |
Stopping Unwanted Fuel Pump Voltage
A P0232 code means the fuel pump power circuit has voltage it should not have. Stuck relays, shorts to power and faulty driver modules cause most cases.
- Listen for the pump with the key off.
- Pull the relay to see if the pump stops.
- Check the driver module if fitted.
- Trace the wiring for a short to power.
Frequently Asked Questions
Why Is My Battery Dead After the P0232 Code Sets?
If the relay or module is stuck on, the fuel pump keeps running after you turn the engine off. A pump draws several amps, so it can drain a healthy battery overnight. Pull the relay or fuse until it is fixed.
Where Is the Fuel Pump Relay?
Most vehicles keep it in the underhood fuse and relay box, and the lid or owner’s manual shows its position. Vehicles with a fuel pump driver module often mount the module on the frame rail, near the spare tire or behind a trim panel in the trunk.
What Is an Inertia Switch?
Some vehicles, especially older Fords, have an inertia switch that cuts fuel pump power after a hard jolt or crash. A bump or pothole can trip it too. It is often in the passenger footwell or trunk, and pressing its reset button restores power.
How Long Does a Fuel Pump Last?
Many fuel pumps last 100,000 miles or more. Running the tank low often, contaminated fuel and a clogged filter shorten their life. A pump that is getting louder, or an engine that loses power on hills, can be early signs of wear.
Can a Weak Battery Cause Fuel Pump Codes?
It can. Low system voltage makes the pump run slower and can drop the feedback voltage the PCM reads. Test the battery and charging system, and clean the battery terminals, before you replace fuel pump parts.