P0945 Hydraulic Pump Relay Circuit/Open

P0945 points to a hydraulic pump relay circuit or open-circuit fault. The controller cannot complete the relay path used to power the hydraulic pump.

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 before proving the relay control circuit and power supply are intact.

Useful checks before replacing parts

Check hydraulic pump relay feed, control, ground, output voltage, fuse supply, connector fit, and relay coil resistance.
Inspect pump wiring, relay socket terminals, module driver output, water intrusion, harness rub points, and voltage drop under load.
Compare pump command with relay output, pump current, pressure build, and pressure sensor response.

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.