P0943 Hydraulic Pressure Unit Cycling Period Too Short

P0943 points to a hydraulic pressure unit cycling period that is too short. The system is rebuilding pressure too often or losing pressure too quickly.

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 replace the pump alone if pressure loss, accumulator leakage, or sensor error is causing short cycling.

Useful checks before replacing parts

Monitor pressure unit cycling interval, pressure sensor data, pump command, hydraulic temperature, and actuator requests during operation.
Inspect for hydraulic leaks, accumulator problems, pressure loss, pump relay sticking, sensor drift, and fluid level or aeration issues.
Check whether frequent cycling appears after long soak, during repeated shifts, at high temperature, or with one actuator command.

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.