Transmission Fluid Pressure Sensor/Switch B Circuit
The P0845 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Pressure Sensor/Switch B Circuit. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $600 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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Common Symptoms
- Check Engine Light illuminated
- Erratic shifting patterns
- Transmission slipping in certain gears
- Vehicle may enter limp mode
Probable Causes (Ranked by Likelihood)
- Faulty transmission fluid pressure sensor B Very High
- Wiring fault in pressure sensor B circuit High
- Corroded connector at pressure sensor B Moderate
- Internal valve body issue affecting B circuit pressure Low
Frequently Asked Questions
What is pressure sensor B vs sensor A?
Transmissions with multiple pressure sensors use A and B to monitor pressure at different points in the hydraulic circuit. Sensor B typically monitors a secondary pressure circuit or specific clutch pack pressure.
Can I drive with P0845?
You can drive short distances, but the transmission may not shift correctly. Prolonged driving can cause additional wear to internal components.
Are pressure sensors A and B interchangeable?
In some vehicles the sensors are the same part number, but they are located in different positions. Always verify the correct part number for each location.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Check transmission fluid level and condition
-
Monitor pressure sensor B data on a scan tool and compare to sensor A
-
Inspect wiring and connector at pressure sensor B for damage
-
Test sensor B resistance and compare to manufacturer specifications
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- 2007-2017 Nissan Rogue (CVT)
- 2008-2018 Honda CR-V
- 2010-2020 Subaru Impreza (CVT)
- 2009-2019 Toyota RAV4
Related Codes
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