English-first OBD-II diagnostics Static, fast, focused lookup pages
CD CheckDTC Garage-grade fault lookup
Open P0300 Try AI Diagnose
Home / Codes / U0106
DTC code page

U0106: Lost Communication With Glow Plug Control Module

Quick answer: The network lost communication with the glow plug control module used on diesel applications.

Drivers also search this fault as lost communication with glow plug module, glow plug module offline, diesel preheat module communication fault.

Severity: medium Family: network Related paths: 12
Meaning

What U0106 usually means

U0106 appears mainly on diesel vehicles and means the glow plug control module stopped talking to the rest of the system. That matters because the glow module is not just a convenience box. On many diesels it influences cold-start quality, preheat timing, and how confidently the powertrain can manage cold operation. The fault can come from module power loss, network issues, or the module itself failing under heat and vibration.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Confirm the vehicle is diesel because U0106 is a diesel-specific branch and changes the diagnostic context immediately.
  • Check battery strength and cranking voltage since cold-weather low voltage can create both preheat and communication complaints.
  • Ask whether the hard-start issue is much worse when cold because that strongly fits glow-module involvement.
Driving risk

Can you keep driving?

U0106 may not strand a warm diesel immediately, but cold starts can become much harder and rougher. Fix it before colder weather or repeat no-start episodes turn it into a bigger problem.

Moderate urgency: This code often allows short-term driving, but the right fix usually comes faster when you diagnose it early instead of waiting for more codes.
Likely causes

Common causes behind this code

  • Glow plug control module power or ground fault
  • CAN or communication-line issue between the glow module and powertrain network
  • Low battery voltage during cold-weather starting
  • Corrosion or water intrusion at the glow plug module connector
  • Internal failure of the glow plug control module

Cause phrases often tied to this code: glow plug module power loss, diesel network issue, corroded module connector, low voltage during cold start, failed glow module.

Diagnostic order

Suggested workflow

  1. Scan all modules and verify whether the glow plug control module communicates directly.
  2. Check module power, grounds, and fuse feeds under load.
  3. Inspect module connectors and harness routing for corrosion, heat damage, or rubbing.
  4. Review companion glow-plug or preheat codes to see whether the issue is communication only or also affects output control.
  5. Replace the module only after proving its feeds and network path are stable.
Avoid guesswork

Common mistakes

  • Applying gasoline-engine logic to a diesel cold-start communication code.
  • Replacing glow plugs when the control module itself is offline.
  • Ignoring battery weakness during cold weather even though low voltage is central to diesel preheat complaints.
Repair path

Practical fix guidance

  • Restore clean power, ground, and communication to the glow plug control module first.
  • If the module itself failed, replace it only after confirming the harness and battery condition will not damage the new unit.
  • After repair, verify cold-start preheat behavior instead of checking only for a cleared code.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to U0106

Useful when the driver knows the wording but not the exact DTC yet.

  • lost communication with glow plug module
  • glow plug module offline
  • diesel preheat module communication fault
Related search intent

Queries this page can answer naturally

  • U0106 code meaning
  • what does U0106 mean
  • lost communication with glow plug control module
  • diesel hard start communication code
FAQ

Quick questions about U0106

Does U0106 matter on a gasoline engine?

No. This is a diesel-oriented communication code because gasoline engines do not use a glow plug control module.

Can a weak battery trigger U0106 in winter?

Yes. Diesel preheat systems are very sensitive to low cranking voltage and poor power supply.

Should glow plugs be replaced first for U0106?

Not unless testing proves they failed too. U0106 says the control module is not communicating, which is a different issue.