P0778 on Kia: How to Diagnose & Fix
Pressure Control Solenoid B Electrical
1 Kia model · 1 documented issue · $400-$1,800 repair
P0778 on Kia by model: symptoms, diagnosis and fix
The A6MF-family 6-speed automatic can develop harsh or erratic shifting, hard 6-to-4 kickdown 'bang,' shift flares, brief neutral feel during up/downshifts, and torque-converter clutch (TCC) shudder. The root cause is wear of the reducing-valve bores in the valve body, which lets line pressure drift out of spec; neglected fluid (SP4-spec) accelerates the wear. The internal wiring harness is also a known high-failure component on this transmission family, producing intermittent solenoid faults. This is a distinct transmission failure mode from the AWD rear-differential coupling noise already documented.
Common Symptoms
- Hard or jerky shifts
- 6-to-4 downshift bang/clunk
- RPM flare or neutral feeling between shifts
- Torque-converter shudder at light cruise
- Delayed engagement into Drive/Reverse
How to Fix
Start with a proper SP4-spec fluid service and a TCM software update if available. Persistent harsh shifting, gear-ratio or solenoid-performance codes are usually resolved by rebuilding or replacing the valve body (with the reducing valves/solenoids), and inspecting the internal harness for abrasion. In severe slip/shudder cases the torque converter is replaced.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Kia UM013-CH059 ATF Type 4(M) / SP-IV transmission fluidOEMKia UM013-CH059
Use only for a Kia-procedure fluid service after level, condition and transmission diagnosis Fitment/availability: 2017-2022 Kia Sportage QL six-speed automatic, both 2.4L GDI and 2.0L T-GDI; the current Kia guide lists total fill 7.1 qt…
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Sources for this issue (2)
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 Kia?
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 Kia it is documented across 1 model: Sportage.
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 Kia?
Published repair estimates on Kia range from $400 to $1,800 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.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.