Code Definition

P0849 — Transmission Fluid Pressure Sensor/Switch B Circuit Intermittent

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0849

P0849 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0849 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0849 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0849 code is set when the vehicle's control module detects intermittent readings from the Transmission Fluid Pressure Sensor/Switch B Circuit. This condition indicates that the sensor or switch is experiencing sporadic, inconsistent signals, which can be due to fluctuations in the transmission fluid pressure or electrical issues within the circuit. The control module relies on stable and consistent readings from this sensor/switch to manage transmission operation, and intermittent signals can lead to incorrect adjustments or diagnoses by the system.

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