P0778 on Nissan: How to Diagnose & Fix
Pressure Control Solenoid B Electrical
1 Nissan model · 1 documented issue · 1 critical · $900-$3,500 repair
P0778 on Nissan by model: symptoms, diagnosis and fix
The Jatco RE5R05A five-speed automatic used in the second-generation Frontier carries its transmission control module bolted directly to the valve body, submerged in hot ATF. That packaging is the weak point: sustained heat cycling and vibration crack solder joints and kill solenoid drivers, while the shift solenoids themselves are delicate and intolerant of any contamination. Owners report slipping between gears, delayed or flared upshifts, refusal to shift above a certain gear, and the transmission dropping into a fixed-gear limp mode. This is documented as a failure in its own right and is distinct from - though badly aggravated by - the coolant-into-ATF radiator failure this platform is also known for, since the resulting gel jams the solenoid plungers and shorts the solenoid wiring. Diagnosis is often mistaken for whole-transmission failure when only the valve body and TCM have gone.
Common Symptoms
- Harsh, delayed or erratic shifting
- Slipping between gears or shift flare
- Stuck in one gear (limp mode)
- Will not shift into higher gears
- Transmission warning light on
How to Fix
Scan transmission codes and inspect ATF for coolant contamination before ordering. If the radiator cooler failed, repair that failure and the cooler circuit first; a contaminated or mechanically damaged transmission may need a rebuild rather than a valve body.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Sunbelt RE5R05A valve body with VIN-programmed TCM$795
2005-2012 Nissan Frontier 2.5L or 4.0L with the RE5R05A five-speed automatic; VIN and plate-code availability must be confirmed.
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Sources for this issue (3)
P0778 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0778 mean on a Nissan?
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 Nissan it is documented across 1 model: Frontier.
What are the most common causes of P0778?
The most common causes of P0778 are: 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). The specific cause varies by vehicle.
How much does it cost to fix P0778 on a Nissan?
Published repair estimates on Nissan range from $900 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0778 on a different make?
View P0778 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.