OBD-II Diagnostic Trouble Code
P0627 — Fuel Pump Control Circuit/Open
P0627 means the ECM detected an open or general fault in the fuel pump A control circuit. That's the circuit that commands the fuel pump relay, the pump driver module, or the lift or transfer pump. The ECM commanded the pump and saw the circuit didn't respond as expected.
Severity 4/5
Truck-relevant
Stop within 50 mi
Severity
Stop within 50 mi
Fuel Pump Control Circuit/Open
Code
P0627
Category
Powertrain
Subsystem
Fuel
Truck-relevant
Yes
What this means for truckers
P0627 (Fuel Pump Control Circuit/Open) — the ECM lost control of the lift pump or transfer pump. Without lift pump, the high-pressure pump starves and engine stalls. Test fuel pressure at the rail to confirm. Common on Ford Power Stroke 6.7L and some Cummins applications. Replacement: $300-800 depending on pump.
Before you replace parts — try this first
P0627 on the Fuel system is most often open control wire or loose connector at the fuel pump, relay or driver module — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Crank-no-start, hard start, stalling, or loss of power under load from low fuel supply. On diesels with an electric lift pump you may hear no pump prime at key-on. Some trucks run normally if a mechanical supply pump keeps fuel flowing, and only the check-engine light comes on.
Common causes
- CommonOpen control wire or loose connector at the fuel pump, relay or driver module ($80–$400)
- CommonFailed fuel pump relay or fuel pump driver module ($60–$500)
- OccasionalFailed fuel or lift pump motor (open winding) ($300–$1200)
- OccasionalBlown fuse in the pump circuit ($20–$150)
- RareFailed ECM pump driver ($1200–$3500)
How to fix
Check the fuel pump fuses and relay, and listen for pump prime at key-on
When to use: First step
Use a scan tool output test to command the pump and check for control signal and power at the pump connector
When to use: To isolate the wiring versus the pump
Check the pump motor resistance and current draw
When to use: When power and ground reach the pump but it doesn't run
Repair the wiring, or replace the relay, driver module or pump
When to use: Based on test results
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P0670 — Glow Plug Control Module Circuit
- → P0671 — Cylinder 1 Glow Plug Circuit
- → P0672 — Cylinder 2 Glow Plug Circuit
- → P0673 — Cylinder 3 Glow Plug Circuit
- → P0674 — Cylinder 4 Glow Plug Circuit
Frequently Asked Questions
Can I drive with code P0627?
Drive with caution. P0627 is severity 4 — stop within ~50 miles. Most commercial diesel codes at this severity (turbo, fuel rail, transmission solenoid) can damage adjacent expensive components if left unrepaired. Get to a service location before highway-speed loads.
How much does it cost to fix P0627 on a commercial truck?
Total repair cost ranges $20–$3500 depending on the root cause. The cheapest fix is usually the first one listed below — Open control wire or loose connector at the fuel pump, relay or driver module — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P0627 fail a DOT inspection?
P0627 itself doesn't automatically fail an inspection, but if the truck is in reduced-power mode (limp mode) at the time of inspection, it WILL be flagged. Most inspectors will note the check engine light but pass the truck if it's running and performance is normal. Fix it before a Level 1 inspection regardless.
What's the difference between P0627 and related codes?
P0627 is closely related to: P0670 (Glow Plug Control Module Circuit), P0671 (Cylinder 1 Glow Plug Circuit), P0672 (Cylinder 2 Glow Plug Circuit), P0673 (Cylinder 3 Glow Plug Circuit). These codes share the same subsystem (fuel) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P0627 is set without the companions, the issue is more isolated.
How do I prevent P0627 from coming back after a repair?
For P0627 (Fuel Pump Control Circuit/Open), prevention centers on the fuel system. Replace fuel filters at the OEM interval — don't stretch them. Use only diesel from high-volume fuel stops (avoid bottom-of-tank fuel at low-traffic stations). Add a water separator if you don't have one. After repair, prime the fuel system per the engine manual.