U0109 on 2018-2024 Ford F-150: Lost Communication With Fuel Pump Control Module Causes and Fixes

What's Unique About the 2018-2024 Ford F-150

Ford has issued multiple Technical Service Bulletins (TSBs) for this exact issue on 2018-2024 F-150s, indicating a known weakness. 🎬 Watch: Diagnosing U0109 lost communication with the control module. The problem is rarely the expensive PCM; instead, it's almost always a fault in the wiring, connector, or ground point for the Fuel Pump Control Module. The module's location on a frame cross-member above the spare tire makes its electrical connections extremely vulnerable to corrosion and physical damage from road spray and debris. Owners on forums frequently report finding the connector full of green and white corrosion or discovering chafed wires inside the loom right near the FPCM.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: This range covers the thirteenth (2018-2020) and fourteenth (2021-2024) generations of the F-150. The underlying cause, related to the FPCM wiring and location, is a known issue across both generations as documented in Ford's technical service bulletins which explicitly cover these model years.

Symptoms You May Notice

• Engine cranks but will not start.
• Sudden engine stalling, sometimes intermittently.
• Loss of power while driving.
• Illuminated Check Engine Light (Malfunction Indicator Lamp).
• Wrench light may be illuminated on the dashboard.
• You may not hear the typical 'hum' of the fuel pump priming when turning the key to the 'ON' position.
• Intermittent no-start that may seem to happen more frequently after heavy rain, a car wash, or driving on wet roads.

Most Likely Causes

1. Wiring Harness or Connector Damage 🔴 High Probability Ford TSBs SSM 52483 and 50661 directly cite this as the primary cause. The harness is routed along the frame and can be damaged by debris, corrosion, or chafing. The connector itself (C4336 or C460) can get moisture inside, or the pins can become loose or corroded. Forum users have found broken and corroded wires inside the wiring loom near the sharp bend where it connects to the FPCM.
   How to confirm: Lower the spare tire to access the FPCM on the frame cross-member. Disconnect the electrical connector and thoroughly inspect for green/white corrosion, pushed-out pins, or damaged wires. A YouTube video on a 2021 F-150 with U0109 showed a corroded, broken power wire found only after dropping the fuel tank to trace the harness. Wiggle the harness while checking for continuity with a multimeter on the power, ground, and CAN bus wires between the FPCM and the PCM.
   Typical fix: Clean the connector terminals with an electrical contact cleaner if corroded. Repair any broken or chafed wires using appropriately sized butt connectors and heat-shrink tubing. If the connector itself is damaged, it must be replaced with a new pigtail, such as Motorcraft WPT-1109.
   Est. part cost: $15-$50 for a connector pigtail
2. Loose or Corroded FPCM Ground 🟡 Medium Probability The ground point is located on the truck's frame, making it susceptible to rust and corrosion. Ford TSB SSM 52483 and others specifically call out inspecting ground G401 on the F-150 for this issue.
   How to confirm: Locate ground G401 on the driver's side frame rail, near the FPCM. Check if the bolt is tight and if there is any rust or corrosion between the ground lug and the frame. A user on an F-150 forum confirmed that simply removing the ground, letting it hang, and re-starting the truck caused an immediate stall, proving its importance.
   Typical fix: Remove the ground bolt, clean the contact surfaces of the wire terminal and the frame down to bare metal using a wire brush or sandpaper, apply dielectric grease to prevent future corrosion, and securely re-fasten the bolt.
   Est. part cost: $0-$5
3. Failed Fuel Pump Control Module (FPCM) 🟡 Medium Probability The module's electronics can fail from heat, vibration, and age. Its location under the truck exposes it to harsh conditions, and older F-150 generations had widespread issues with the module itself corroding and failing. However, for this generation, TSBs strongly advise checking wiring first.
   How to confirm: After confirming the wiring, connector, fuse, and ground are all in perfect condition, the module itself becomes the primary suspect. Substitution with a known-good part is the most common confirmation method. Do not replace this part until all other steps have been exhausted.
   Typical fix: Replace the Fuel Pump Control Module. This is typically a plug-and-play part that does not require programming on this platform.
   Est. part cost: $60-$150
4. Blown Fuse ⚪ Low Probability While not as common as wiring faults for this specific code, a blown fuse will cut power to the FPCM and cause a communication loss. This can happen due to a short circuit in the harness.
   How to confirm: For 2018-2020 models, check fuse #27 (20A) in the under-hood fuse box (Battery Junction Box). For 2021+ models, this may be labeled as fuse #28 (20A) for the 'Fuel pump'. Always verify with your owner's manual.
   Typical fix: Replace the blown fuse with one of the same amperage rating. If the new fuse blows immediately, there is a short circuit in the wiring to the FPCM that must be found and repaired.
   Est. part cost: $1-$5

Rare But Worth Checking

• Powertrain Control Module (PCM) Fault: This is extremely rare. The PCM is a robust component. All other possibilities, especially wiring and the FPCM itself, should be exhaustively ruled out before considering PCM replacement.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner. Confirm U0109 is present, and note any other codes like P0627, P025A, or P008A.
2. Check the fuse for the Fuel Pump Control Module (typically F28 or F27, a 20A fuse) in the under-hood fuse box (Battery Junction Box). Replace if blown.
3. Lower the spare tire to gain access to the rear frame cross-member.
4. Locate the Fuel Pump Control Module (FPCM) mounted to the cross-member.
5. Visually inspect the module and its connector for obvious physical damage or corrosion.
6. Carefully disconnect the electrical connector (C4336/C460). Inspect both the harness side and the module side for bent pins, pushed-out pins, or any signs of corrosion (green or white powder).
7. With the key on, use a multimeter to check for battery voltage at the power supply pin of the FPCM connector. A detailed YouTube repair showed a failure to get voltage at pin 1 of connector C4336, indicating an open wire.
8. Follow the wiring harness from the connector, looking for any spots where it might be rubbing against the frame or other components. Pay close attention to the area where the harness bends to meet the connector.
9. Locate the FPCM ground wire on the frame (Ground G401). Ensure it is clean, free of rust, and securely fastened.
10. If all wiring, the connector, and the ground are confirmed to be in good condition, the FPCM itself is the most likely failed component.
11. Replace the FPCM, clear the codes, and start the vehicle to confirm the repair.

Parts You'll Likely Need

• Fuel Pump Control Module (OEM #HL3Z-9D370-B (verify with VIN, may be superseded by PR3Z-9D370-B)) — This module is the most common part to be replaced after wiring issues are ruled out. Its location makes it prone to failure from the elements.
  Trusted brands: Motorcraft, Dorman, Standard Motor Products
  OEM price range: $70-$150
  Aftermarket price range: $50-$100
• FPCM Connector Pigtail (OEM #Motorcraft WPT-1109 (Service P/N 3U2Z-14S411-CEB)) — If the connector itself is corroded or damaged beyond cleaning, a new pigtail will be needed to ensure a solid connection.
  Trusted brands: Motorcraft, Dorman
  OEM price range: $30-$50
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0627 — Stands for 'Fuel Pump A Control Circuit Open'. This code often appears with U0109 because the wiring issue that causes the communication loss also creates an open circuit. Ford TSB SSM 52483 lists these codes together.
• P025A — Stands for 'Fuel Pump Module Control Circuit Open'. Similar to P0627, this points to the same underlying wiring fault and is frequently cited in the same TSBs as U0109.
• P008A — Stands for 'Low Pressure Fuel System Pressure - Too Low'. This is a direct consequence of the FPCM not communicating and therefore not running the fuel pump at the correct pressure. TSB SSM 52483 also lists this code.

Technical Service Bulletins (TSBs) & Recalls

• SSM 52483: Mentions U0109 on 2018-2024 F-150s and advises checking the FPCM harness, connector C460/C4336, and ground G401 before performing diagnostics or replacing parts.
• SSM 50661: Cites U0109 on 2018-2022 F-150s and points to harness disconnects, pin push-outs, or loose/corroded grounds (specifically G401 for F-150).
• SSM 49618: An earlier bulletin for 2018-2021 F-150s that also identifies harness/connector issues as the likely cause for U0109.

Platform-Specific Known Issues

• Ford has released multiple Technical Service Bulletins (TSBs) regarding U0109 and related fuel system codes, including SSM 52483, SSM 51306, SSM 50661, and SSM 49618. All point to wiring harness or connector issues as the primary cause.

Mechanic-Grade Diagnostic Values

• FPCM Power Supply Voltage — expected: 11.5 - 12.5 Volts (Battery Voltage). Failure: 0V or significantly low voltage indicates an open or short in the power supply wire or a blown fuse.
• CAN Bus Network Resistance — expected: Approximately 60 Ohms. Failure: A reading of 120 Ohms suggests one of the two terminating resistors is offline or there's a break in the CAN bus wiring. An open circuit (OL) indicates a broken wire.
• FORScan Live Data PID: FLP — expected: Varies with demand, but should respond to throttle input.. Failure: A static or unresponsive value when monitoring 'Low Side Fuel Pressure' (FLP) can indicate a problem with the pump or control module.

Scan Tool Commands That Help

• FORScan / Ford IDS: On-Demand Self-Test (ODST) or Key On Engine Off (KOEO) Test — Running a network test or a KOEO self-test can help verify if the communication loss is current. The PCM will attempt to communicate with all modules on the network, and a failure to communicate with the FPCM will be flagged immediately.
• FORScan / Ford IDS: Monitor PIDs: FLP (Low Side Fuel Pressure), FLP_DSD (Low Side Fuel Pressure Desired) — Monitoring these PIDs provides insight into what the PCM is requesting versus what the system is actually delivering (if anything). A desired pressure with zero actual pressure points directly to a failure in the low-pressure fuel system, consistent with U0109.

Wiring & Ground Locations

• C4336 — The main electrical connector at the Fuel Pump Control Module, located on the frame cross-member above the spare tire.. This is the primary point of failure due to corrosion and wiring damage. TSBs consistently point to issues at this connector.
• C4336 - Pin 1 — Pin 1 of the FPCM connector.. This is the main power supply wire to the module. A technician in a video diagnosed a no-start U0109 by confirming no voltage at this pin, leading to the discovery of a broken wire.
• G401 — On the left (driver's side) rear frame rail, near the FPCM.. This is the main ground point for the Fuel Pump Control Module. Corrosion at this point can cause high resistance, leading to intermittent operation and communication faults.
• C1591 — A large, intermediate harness connector located along the driver's side frame rail, between the front of the truck and the FPCM.. A technician traced a broken power wire (for Pin 1 at the FPCM) through this connector. The break was found in the harness section between C1591 and the FPCM, hidden behind the fuel tank.

Real Owner Repair Stories

• YouTube channel 'Can Auto Repair' (2021 Ford F-150) — Intermittent no-start, would sometimes start but then shut off. Codes P0627 and U0109 were present.
  ❌ Tried (didn't work) Initial inspection of the FPCM connector and ground point (G401) showed no obvious issues.
  ✅ What actually fixed it The technician found there was no voltage at Pin 1 of the FPCM connector (C4336). After tracing the power wire back, a break was discovered in the harness behind the fuel tank, between the intermediate connector C1591 and the FPCM. Repairing the broken wire resolved the issue.
• YouTube channel 'Daniel “Rescue Moving Services” Rescue Movers' (2013 Ford F-150 EcoBoost 3.5L (Note: Pre-dates the specified range but demonstrates a common failure pattern)) — Crank no-start. Codes P025A, P00C6, U0109.
  ❌ Tried (didn't work) Replaced the Fuel Pump Driver Module (FPDM/FPCM).
  ✅ What actually fixed it The actual problem was a blown 20A fuse for the fuel pump (Fuse #27 in this model year) located in the under-hood fuse box. Replacing the fuse fixed the no-start condition.

OEM Part Supersession History

• HL3Z-9D370-A → HL3Z-9D370-B — Standard part revision by the manufacturer.

Model Year Variations Within This Range

• 2018-2020 vs 2021-2024: The fuse location for the fuel pump may differ. On 2018-2020 models, it is often cited as fuse #27 (20A) in the under-hood fuse box. On 2021+ models, it may be fuse #28 (20A). Always confirm with the owner's manual for the specific vehicle.