P0778 fault code: what it means

P0778: Pressure control solenoid B electrical fault (6-speed automatic).

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

faulty pressure control solenoid B
wiring or connector fault
TCM fault

P0778 by make

Kia

Pressure control solenoid B electrical fault (6-speed automatic).

Usual causes: faulty pressure control solenoid B; wiring or connector fault; TCM fault

Mercedes-Benz

7G-Tronic pressure control solenoid B electrical fault; can cause harsh shifts or limp mode.

Usual causes: faulty solenoid (valve body); conductor plate fault; leaking 13-pin connector

Nissan

CVT pressure control solenoid B electrical fault (circuit reading out of range).

Usual causes: solenoid B / valve body fault; transmission wiring or connector fault; TCM fault

Subaru

Subaru 4-speed auto (4EAT): 2-4 brake pressure control (duty) solenoid circuit fault. Can cause harsh or missed shifts.

Usual causes: faulty 2-4 brake duty solenoid; wiring or connector fault at the valve body; worn or burnt transmission fluid

What the repair usually costs

Automatic transmission fluid service, drain and refill (car)NZ$210–NZ$470 · A$210–A$450
Automatic transmission fluid service (SUV / ute / 4WD)NZ$300–NZ$680 · A$290–A$650
Automatic transmission service with pan / filter (European ZF / Mercedes)NZ$610–NZ$1,240 · A$570–A$1,160
CVT fluid service (car)NZ$250–NZ$580 · A$250–A$550

Not sure what P0778 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.