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U067A Lost Communication With Transmission Fluid Pressure Sensor/Switch B

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Sensor B is the second pressure measuring point. In GM's CVT table 25OBDG03A it reads the secondary pulley, whose pressure sets the clamping force on the belt; its plausibility check runs only above 1,200 rpm with line pressure over 1,000 kPa and a secondary command above 500 kPa. In GM's 24OBDG07 B belongs to clutch 2, fed from its own reference VREF2, and Ford's 2024 summary checks TFP B with P0846 to P0848. U067A stands for a digital sensor B whose messages have stopped. No manufacturer documents this code publicly. With the clamping or clutch pressure unknown, the controller has to work with assumed values, which can mean firmer shifts, limited torque or a fixed gear. If A is still readable, the fault sits in B's own branch.

Likely causes

Internal wiring to sensor B damaged
Pressure sensor B failed
Separate sensor supply for B faulty
Transmission controller fault

Symptoms

  • Firm shifts or engagement
  • Reduced engine torque, limp mode
  • Warning light on

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,200
Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

transmission fluid pressure sensor bvehicle bus wiring

Related codes

U0679P0845P0846P0847P0848P0849

References: gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.