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P0628 typically points to the fuel pump driver module (FPDM) - not the pump itself. On many Fords, the FPDM lives under the rear bumper or near the spare and corrodes from road salt. Inspect there before dropping the tank for a pump. See top-rated scanners on Amazon ↗
🗺 Where Is the Problem?
Blueprint view - P0628 system overview
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0628 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
50%
#1 - Most Likely
Failed Fuel Pump Driver Module (FPDM)
The PWM driver module that controls fuel pump speed has failed. Common on Ford trucks, F-150s, and Mustangs after 80k miles, especially in salt-belt vehicles. Replacement is straightforward once located.
🔩 Part
$80–$300
👨🔧 Labor
$60–$180
⚡ DIY Difficulty
Medium
30%
#2 - Check Second
Wiring/Connector Corrosion
The FPDM connector and chassis ground are exposed to weather. Green corrosion on the connector pins or a failed ground point produces a low signal. Clean and seal before replacing the module.
🔩 Part
$10–$60
👨🔧 Labor
$60–$180
⚡ DIY Difficulty
Medium
20%
#3 - Less Common
Failing Fuel Pump
A pump that's drawing excess current (worn brushes, restricted strainer) can over-load the FPDM and trigger a low-side fault. Test pump current draw before replacing the module.
🔩 Part
$120–$400
👨🔧 Labor
$200–$500
⚡ DIY Difficulty
Hard
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Locate and Inspect the FPDM - On most Fords, it's on the frame rail or under the bumper. Look for green corrosion on the connector and any wet/discolored module housing.
- Test Fuel Pump Current Draw - With an amp clamp on the pump's power wire, verify current is in spec. A pump pulling 9A+ on a system rated for 5–7A is overloading the module.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need