P0847 — Transmission Fluid Pressure Sensor/Switch B Circuit Low

P0847: Transmission Fluid Pressure Sensor/Switch B Circuit Low — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Transmission Fluid Pressure Sensor/Switch B Circuit Low. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Transmission warning or abnormal gear changes may occur.
  • A restricted operating mode can be activated in some vehicles.

Possible causes

  • Open or damaged wiring, poor connector contacts, or a faulty pressure sensor/switch B can pull its electrical signal low.
  • Low signal voltage does not, on its own, establish that hydraulic fluid pressure is low.

What to check

  • Confirm P0847 and inspect sensor B connectors, harness and any related transmission faults.
  • Check the sensor circuit against manufacturer voltage specifications; assess fluid level by the vehicle procedure as a separate hydraulic check.

Also written as: P0847-00, P084700, PO847 (some scan tools add the fault-type byte, e.g. -00).