OBD-II code · Network

U01B6 Lost Communication With Fuel Heater Control Module

ECU lost communication with fuel heater control module (heats diesel fuel to prevent waxing in cold).

Is it safe to drive with U01B6?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyModule unpowered
  • Less likelyGateway module routing CAN messages incorrectly
  • Less likelyCAN terminating resistor (120 Ω) drifted out of spec

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.5–3 h
Emissions test
Likely to fail
Parts involved
Fuel Heater Module, Can Bus

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.