Network
generic / SAE
U0666
Lost Communication With Reductant Pressure Sensor
The vehicle bus reports loss of communication with smart reductant (DEF/AdBlue) pressure sensor. Pump pressure feedback for the SCR dosing system is unavailable.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number6 / 66
Possible causes
- Bus wiring open or shorted high
- Module without power or ground medium
- Module failed medium
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
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 200–1200 €
- Estimated time: 0.5–3 h
- Component: reductant pressure sensor
- Component: vehicle bus wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012