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P0778 Transmission
Pressure Control Solenoid B Electrical
P0778 means an electrical fault in transmission pressure control solenoid B. This solenoid regulates pressure for certain circuits, so faults affect shift feel and can damage the transmission.
🚗 Risky. Pressure control faults can cause slipping and internal damage. Address it soon.
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🎯 Top Causes, Ranked by Likelihood
#1 Faulty pressure control solenoid B $150-$600
The solenoid has an electrical fault and cannot regulate pressure.
#2 Wiring or connector fault $40-$300
Damaged wiring or a corroded connector in the circuit.
#3 Low or contaminated fluid $80-$300
Poor fluid disrupts solenoid operation.
#4 Valve body wear $300-$1200
Worn passages affect pressure control.
🩺 Common Symptoms Harsh or slipping shifts Check engine light Delayed engagement Limp mode
💰 Repair Cost: DIY vs Shop
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🔧 How to Diagnose P0778 1 Check the fluid level and condition
2 Inspect the solenoid wiring and connector
3 Test pressure control solenoid B
4 Service the valve body if needed
❓ Frequently Asked Questions Can I drive with P0778?
Risky. Improper pressure control can damage the transmission. Fix it soon.
How much to fix P0778?
A solenoid is often $200-$600; valve body work costs more.
Is P0778 serious?
Yes. Pressure control is critical to transmission health.
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