U0105 — Data bus: Injector Control Module – No Communication #

Note: Code title wording may vary depending on the vehicle manufacturer (OEM).

• Lost Communication With Fuel Injector Control Module (GM, Ford)
• Injector Control Module No Communication (Chevrolet)
• No Communication With Injector Control Module (Toyota, Nissan)
• Lost Comm With FICM (Fuel Injection Control Module) (Dodge, Ram)

Summary for code U0105 #

The U0105 diagnostic trouble code (DTC) flags a loss of communication between the vehicle’s main computer—known as the Powertrain Control Module (PCM)—and the Injector Control Module (ICM) via the data bus. The data bus, often the CAN (Controller Area Network), is a digital network linking all major control modules in your vehicle for seamless operation. Without this communication, fuel injection timing and quantity may be compromised, affecting engine performance. U0105 is a network communication fault rather than a direct injector or fuel delivery issue. This code typically means that the PCM is unable to receive data from the ICM, which can result in a range of symptoms from hard starting to a no-start condition.

Common symptoms for code U0105 #

A vehicle registering the U0105 code may exhibit a variety of telltale signs. Depending on the model, some symptoms can be subtle while others are immediately disruptive. Most commonly, you’ll notice performance issues since the PCM cannot properly control fuel injection without the ICM’s feedback. Watch for these indicators:

• Engine hard to start or fails to start
• Rough idle or stalling
• Reduced engine power or limp mode activation
• Check Engine Light (CEL) illuminated
• Poor acceleration or hesitation
• Intermittent loss of power
• Other related communication DTCs stored

Likely causes for code U0105 #

The U0105 code is most often triggered by wiring or network issues, but several deeper causes are possible. The following are ranked in order of frequency and likelihood:

1. Faulty or damaged wiring/connectors between ICM and PCM (broken wire, corrosion, loose pins).
2. Failed Injector Control Module (ICM)—the module itself may be malfunctioning internally.
3. Power or ground supply issue to the ICM (blown fuse, poor ground connection).
4. CAN bus (data network) fault—short to ground, short to power, open circuit.
5. Faulty PCM (rare, but possible if all else checks out).
6. Aftermarket accessories interfering with the data bus (alarm systems, remote starters, etc.).

Step-by-step diagnosis for code U0105 #

Diagnosing U0105 should be systematic to avoid unnecessary part replacement. In most cases, a careful check of the wiring and network is the fastest route to the cause. Here’s how a professional technician would approach it:

• 1. Confirm the code: Use a professional scan tool to verify U0105 is present and note any other related DTCs.
• 2. Inspect wiring/connectors: Visually check the harness between the PCM and ICM for damage, corrosion, or loose connections.
• 3. Check ICM power and ground: With a multimeter, verify that the ICM is receiving proper voltage and has a solid ground.
• 4. Test network integrity: Use a scope or network tester to check the CAN bus for shorts, opens, or abnormal resistance (60 ohms is typical across CAN lines).
• 5. Attempt module communication: With a scan tool, try direct communication with the ICM. Failure confirms a deeper module or network problem.
• 6. Substitute known-good module (if accessible): If available, swap in a working ICM to verify module failure.
• 7. Check for aftermarket equipment: Remove or disconnect any non-OEM electronics that could affect the data bus.

Possible repairs for code U0105 #

Once the root cause is identified, repairs should directly address the fault. Here’s what may be involved:

• Repair or replace damaged wiring/connectors between PCM and ICM.
• Replace faulty Injector Control Module (ICM) if it fails power/ground checks or cannot be reached by the scan tool.
• Restore power or ground by replacing blown fuses or cleaning ground points.
• Correct CAN bus issues by fixing shorts, opens, or replacing corroded network connectors.
• Replace the PCM only after exhaustive testing rules out all other possibilities (rare).
• Remove or properly install aftermarket accessories interfering with data communication.

Can you drive with code U0105? #

Generally, driving with U0105 is not recommended. In some vehicles, the engine may still run—albeit poorly—but in many cases, you’ll experience hard starting, stalling, or even a complete no-start. Even if the car starts, you risk damaging the engine or getting stranded, since the PCM cannot control fuel delivery accurately. If you see U0105, have the vehicle checked and repaired before regular use resumes.

Vehicles most affected by code U0105 #

While U0105 can technically appear on any modern vehicle using an ICM and networked modules, it’s more frequently seen in certain diesel trucks and vehicles with advanced fuel management. These platforms are especially susceptible:

• Chevrolet Silverado (diesel models)
• GMC Sierra (diesel models)
• Ford F-Series (with Fuel Injection Control Module/FICM)
• Dodge Ram (diesel variants)
• Nissan Titan XD (diesel)
• Toyota Tundra (diesel, select markets)

Frequent mistakes & best practices for code U0105 #

Technicians and DIYers can fall into traps with U0105, so keeping these best practices in mind can save time and money:

• Rushing to replace the ICM without checking wiring or power/ground first.
• Overlooking corroded connectors—minor corrosion can break network communication.
• Ignoring other communication codes that could indicate a broader network issue.
• Neglecting to check for aftermarket electronics that disrupt the CAN bus.
• Not performing a full system scan—multiple network codes can reveal the true root cause.

Quick FAQ for code U0105 #

Here are quick answers to common questions about the U0105 code:

• Q: Will clearing the code fix the problem?
  A: No. The code will return unless the underlying communication fault is resolved.
• Q: Can a weak battery cause U0105?
  A: Yes, a weak battery or poor ground can disrupt module communication, especially at startup.
• Q: Do I need a dealer scan tool to diagnose U0105?
  A: Not always—a quality aftermarket scan tool that supports OEM-level diagnostics is usually sufficient.