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TuningBot DTC Database · v4.37.15

U0666 Lost Communication With Reductant Pressure Sensor

Generic (OBD-II) interpretation in the TuningBot DTC database.

U · NetworkEmissionsOBD2

What U0666 means

U0666
Lost Communication With Reductant Pressure Sensor Generic · emissions Data confidence 65%

The control module stopped receiving expected network messages from the Reductant Pressure Sensor node on the vehicle communication bus.

Symptoms

  • MIL or SCR/AdBlue warning illuminated
  • Possible start-count-down or torque limitation on some applications

Possible causes

  • Reductant quality or level fault
  • Dosing valve or supply module fault
  • NOx sensor fault
  • Frozen or crystallized reductant lines
  • Wiring or connector fault

Recommended checks

  • Read NOx sensor values and dosing system status
  • Check reductant level and quality data
  • Inspect dosing valve, lines and heater operation
  • Check wiring and connectors of the SCR components
  • Check for OEM technical bulletins and software updates

Related and nearby codes

U06 range
U0600U0601U0602U0603U0604U0605U0606U0607U0608U0609U060AU060BU060CU060DU060EU060FU0610U0611

How to read U0666

U

Network: communication between control units.

0

Generic SAE-standard code: same meaning on every make.

666

Specific fault index within the subsystem.

Frequently asked questions about U0666

What does U0666 mean?

Lost Communication With Reductant Pressure Sensor. The control module stopped receiving expected network messages from the Reductant Pressure Sensor node on the vehicle communication bus.

Is U0666 generic or manufacturer-specific?

U0666 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U0666 at file level?

Not guaranteed. Powertrain (P) codes can be reliably disabled in the ECU calibration, but body, chassis and network codes depend on the specific control unit and how the fault is implemented - some can be handled, some cannot. Ask for a quote and our engineers will check your file and tell you, free of charge, whether U0666 is removable in your case.

Other file services

Stage 1/2/3 TuningDPF RemovalEGR RemovalAdBlue / SCR RemovalDTC RemovalIMMO OFFSpeed Limiter (Vmax)

Understand the system behind this code: SCR / AdBlue System

ECU tuningDyno-tested results by model and engine See the results →

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