P0846: Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance
What to do
Ask whether both pressure sensors were compared. If they disagree, the loss is somewhere between them — commonly the valve body, which is usually repairable rather than a rebuild.
What this code means
The second pressure reading is valid but does not match expectation. Read it against sensor A rather than alone: agreement between the two points at a shared cause such as fluid level or the pump, while disagreement locates a restriction or a leak in the path between them — most often a worn valve body bore letting pressure escape on its way to a clutch.
That second case is the encouraging one, because a worn valve body is repairable with oversized valves and sleeve kits rather than replaced, and it is a much smaller job than anything internal.
Likely causes
Start here
- Worn valve body · specialist
- Low or degraded transmission fluid · easy
- Faulty pressure control solenoid · moderate
Less common
- Restricted transmission fluid filter · moderate
- Faulty transmission fluid pressure sensor · moderate
- Worn clutch packs · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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