P0778 on Toyota
Pressure Control Solenoid B Electrical
P0778 on Toyota vehicles indicates pressure control solenoid b electrical. Au7o has documented this code across 1 Toyota model — most commonly on 4Runner. This is a transmission code. Pressure control solenoids regulate the hydraulic fluid pressure that applies the transmission's clutches for smooth, firm gear changes. P0778 specifically flags an electrical fault with Pressure Control Solenoid 'B' — the transmission control module sees that the solenoid's circuit is open, shorted, or drawing current outside the normal range. Symptoms can include harsh or slipping shifts, incorrect line pressure, or the transmission entering limp mode to protect itself. Typical repair costs on Toyota range from $150 to $1,500, depending on the specific model and root cause.
Common Causes of P0778
- •Failed Pressure Control Solenoid B (electrical fault)
- •Damaged wiring or corroded connector to the solenoid
- •Low, dirty, or contaminated transmission fluid
- •Short to power or ground in the solenoid circuit
- •Internal valve body wear or debris
- •Clogged solenoid screen or fluid passage
- •Faulty transmission control module (less common)
P0778 on Toyota by Model
Toyota 4Runner(1 issue)
- High-Mileage Harsh / Jerky Automatic Shifting from Valve-Body Pressure Issues2003-2024
On higher-mileage 4Runner automatics owners report harsh/abrupt shifts, jerky 3-2 downshifts, unstable RPM blips while coasting near 40 mph, and delayed engagement. The most common mechanical cause is valve-body pressure control wear - a sticking pressure-regulator or throttle valve, or a worn shift solenoid - which raises line pressure and slams the shifts, separate from the torque-converter shudder issue. RepairPal logs hundreds of reports of these trucks not shifting correctly at high mileage. Long-neglected, dark/burnt ATF accelerates it.
Looking for P0778 on a different make?
View P0778 across all makes →Frequently Asked Questions
What does P0778 mean on Toyota?▼
P0778 stands for "Pressure Control Solenoid B Electrical." This is a transmission code. Pressure control solenoids regulate the hydraulic fluid pressure that applies the transmission's clutches for smooth, firm gear changes. P0778 specifically flags an electrical fault with Pressure Control Solenoid 'B' — the transmission control module sees that the solenoid's circuit is open, shorted, or drawing current outside the normal range. Symptoms can include harsh or slipping shifts, incorrect line pressure, or the transmission entering limp mode to protect itself. On Toyota specifically, this code is documented across 1 model.
What causes P0778 on Toyota vehicles?▼
Common causes on Toyota: Failed Pressure Control Solenoid B (electrical fault), Damaged wiring or corroded connector to the solenoid, Low, dirty, or contaminated transmission fluid, Short to power or ground in the solenoid circuit, Internal valve body wear or debris. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0778 on a Toyota?▼
Repair costs on Toyota range from $150 to $1,500, depending on the specific model and root cause.
Which Toyota models have P0778 documented?▼
Au7o has documented P0778 on 1 Toyota model: 4Runner.