What does code P1121 mean?

Q: What does code P1121 mean?

Neutral Position Switch Circuit Low Input AT Vehicles. P1121 on Subaru automatic-transmission vehicles means the transmission control module (TCM) has detected a low-input condition on the neutral position switch circuit, which tells the computer whether the selector lever is in neutral. The TCM expects a specific voltage signal from the switch and sees it pulled low, so it cannot reliably confirm neutral position and may set this code as a result.

DTC codes / Subaru codes / P1121

P1121 · SubaruNeutral Position Switch Circuit Low Input AT Vehicles

P1121 on Subaru automatic-transmission vehicles means the transmission control module (TCM) has detected a low-input condition on the neutral position switch circuit, which tells the computer whether the selector lever is in neutral. The TCM expects a specific voltage signal from the switch and sees it pulled low, so it cannot reliably confirm neutral position and may set this code as a result.

SystemPowertrain

Code typeSubaru specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Guidance is general and written for Subaru vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.