P0778 on Jaguar
Pressure Control Solenoid B Electrical
P0778 on Jaguar vehicles indicates pressure control solenoid b electrical. Au7o has documented this code across 1 Jaguar model — most commonly on XK. 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 Jaguar range from $900 to $3,000, 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 Jaguar by Model
Jaguar XK(1 issue)
- ZF 6HP Automatic Transmission Mechatronic Bridge-Seal / Sealing-Sleeve Failure2007-2014
The ZF 6HP26 (2006-2009 4.2L cars) and ZF 6HP28 (2009-2014 5.0L cars) automatic used in the X150 XK develops internal hydraulic-pressure loss as the mechatronic unit ages. The 'bridge seal' adapter (the figure-8 sealing sleeve between the valve body/mechatronic and the transmission case) hardens and cracks, and the conductor plate/solenoids degrade, causing loss of line pressure. This is the single most common ZF 6HP fault and owners frequently misdiagnose it as a dead gearbox, replacing the whole unit when only the mechatronic seal or module is at fault. ATF that is never changed (Jaguar marketed it as fill-for-life) accelerates the failure. Well documented across the shared ZF 6HP platform (also used by BMW, Land Rover, Bentley, Maserati).
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View P0778 across all makes →Frequently Asked Questions
What does P0778 mean on Jaguar?▼
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 Jaguar specifically, this code is documented across 1 model.
What causes P0778 on Jaguar vehicles?▼
Common causes on Jaguar: 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 Jaguar?▼
Repair costs on Jaguar range from $900 to $3,000, depending on the specific model and root cause.
Which Jaguar models have P0778 documented?▼
Au7o has documented P0778 on 1 Jaguar model: XK.