OBD-II code · Powertrain (generic)

P0846 Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance

The transmission fluid pressure sensor/switch B reports a circuit range/performance fault. Hydraulic pressure feedback for shift control is unreliable on this channel.

Is it safe to drive with P0846?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelySensor offset drifted
  • PossibleAerated fluid affects pressure
  • Less likelySensor element aged beyond calibration window

Symptoms

  • Check engine or transmission warning light on
  • Harsh, delayed, or missing shifts
  • Possible limp mode (locked in one gear)
  • Slipping or shuddering during gear changes

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
1–4 h
Emissions test
Usually unaffected
Parts involved
Tfp Sensor B, Wiring Harness, Tcm

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