OBD-II Diagnostic Trouble Code
U0105 — Lost Communication With Fuel Injector Control Module
U0105 sets when the ECM stops receiving messages from the fuel injector control module (FICM), used on engines such as the Ford 6.0L and Navistar VT365. The FICM powers and fires the injectors, so communication loss usually means the FICM lost power, ground or network, or failed internally. Most common-rail heavy diesels drive injectors directly from the ECM and have no separate FICM, so this code applies only where one is fitted.
Severity 5/5
Truck-relevant
Stop now
Severity
Stop now — do not drive
Lost Communication With Fuel Injector Control Module
Code
U0105
Category
Network
Subsystem
Network
Truck-relevant
Yes
What this means for truckers
U0105 (Lost Communication With Fuel Injector Control Module) — see existing FICM context.
Before you replace parts — try this first
U0105 on the Network system is most often weak batteries or poor battery cables causing ficm low voltage — 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
Hard start or no-start, especially cold, rough running, misfire, stalling or engine shutdown. Check-engine light with injector-related codes is common.
Common causes
- CommonWeak batteries or poor battery cables causing FICM low voltage ($150–$600)
- CommonFICM internal power supply failure ($600–$1500)
- OccasionalCorroded or loose FICM connectors or ground ($100–$400)
- OccasionalDamaged CAN wiring between ECM and FICM ($150–$600)
- RareCharging system fault ($300–$800)
How to fix
Load test batteries and check charging voltage and cables
When to use: First step, especially with cold-start complaints
Monitor FICM supply and output voltage with a scan tool during cranking
When to use: To confirm a weak FICM power supply
Inspect FICM connectors and grounds
When to use: When voltage drops intermittently
Repair or replace the FICM
When to use: When battery and wiring are good but FICM voltage or communication fails
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
- → U0100 — Lost Communication With ECM/PCM A
- → U0101 — Lost Communication With TCM
- → U0102 — Lost Communication With Transfer Case Control Module
- → U0103 — Lost Communication With Gear Shift Module
- → U0104 — Lost Communication With Cruise Control Module
Frequently Asked Questions
Can I drive with code U0105?
No — U0105 is severity 5. Stop and tow if you're not near a service location. Continuing to drive can cause catastrophic engine damage. The cost of a tow ($300–800) is small compared to the cost of an engine rebuild ($15,000+).
How much does it cost to fix U0105 on a commercial truck?
Total repair cost ranges $100–$1500 depending on the root cause. The cheapest fix is usually the first one listed below — Weak batteries or poor battery cables causing FICM low voltage — 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 U0105 fail a DOT inspection?
U0105 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between U0105 and related codes?
U0105 is closely related to: U0100 (Lost Communication With ECM/PCM A), U0101 (Lost Communication With TCM), U0102 (Lost Communication With Transfer Case Control Module), U0103 (Lost Communication With Gear Shift Module). These codes share the same subsystem (network) 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 U0105 is set without the companions, the issue is more isolated.
How do I prevent U0105 from coming back after a repair?
For U0105 (Lost Communication With Fuel Injector Control Module), prevention centers on the network system. Pay attention to ground connections at every PM — bad grounds are 70% of communication codes. Inspect harness routing for chafe points. Don't disconnect modules with the key on.