P0778 Pressure Control Solenoid B Electrical

P0778 points to an electrical fault in pressure control solenoid B. The circuit is abnormal before hydraulic diagnosis should take priority.

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 condemn hydraulic components until the pressure-control solenoid B circuit has been tested electrically.

Useful checks before replacing parts

Check pressure control solenoid B power, control circuit, internal harness, case connector, and terminal condition.
Measure circuit resistance or current using the transmission service procedure and compare with known-good circuits.
Inspect shared transmission power feeds and grounds when multiple pressure-control or shift-solenoid codes are present.

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.