2019 Subaru Outback - P0851 Neutral Switch Circuit Low

Question

I have a 2019 Outback with 60k miles. Yesterday, the dashboard lit up like a Christmas tree—CEL, Brake light flashing, and the EyeSight system turned itself off. The car drives fine, shifts smoothly (for a CVT), and I don't notice any mechanical issues.

My scanner shows P0851 - Neutral Switch Input Circuit Low. Does this mean the transmission doesn't know what gear it's in? I'm worried this is going to be an expensive transmission repair since it's a CVT. I tried clearing the code, but it returns the second I shift from Park into Drive.

BackyardBilly · Accepted Answer

✅ Confirmed fix: This is almost always caused by a failed stop lamp switch or a misadjusted range sensor on the side of the transmission. However, in this specific case, it was the transmission range sensor (neutral safety switch) located on the side of the CVT case.

Road salt and moisture had corroded the connector pins. I replaced the Range Sensor (Part #82221AL000) and cleaned the harness connector with electrical contact cleaner. Once replaced, the computer was able to correctly see the voltage from the switch in Park/Neutral, and all the EyeSight/Brake warnings cleared immediately.

EuroEricaW · Answer

Double check your battery voltage. Subaru EyeSight systems are extremely sensitive to voltage. If your battery is putting out 12.1V or less, the CAN-bus modules start throwing 'Low Circuit' codes for sensors that are actually fine. Have you had the battery load tested?

2019 Subaru Outback - P0851 Neutral Switch Circuit Low

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