P0852 Park/Neutral Switch Input Circuit High

P0852 points to a high signal in the park or neutral switch input circuit. The module sees an open, short-to-voltage, or above-range signal.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Transmission
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume the transmission is in the wrong range until the high input circuit is tested.

Useful checks before replacing parts

Check park/neutral signal voltage, ground path, connector condition, open circuits, short-to-voltage faults, and switch adjustment.
Compare scan-tool park/neutral status with actual shifter position and starter interlock behavior in every range.
Inspect recent transmission, shifter, or harness work that could leave the input circuit misadjusted or disconnected.

Related OBD-II codes

These nearby transmission entries can help compare wording and fault area. They may share the same verification status as the source database.