P0778 OBD-II Trouble Code: Pressure Control Solenoid B Electrical

Our certified mechanics come to you · Get a fair and transparent estimate upfront

EXCELLENT RATING ON

Cost of diagnosing the P0778 code

P0778 is a diagnostic trouble code (DTC) for "Pressure Control Solenoid B Electrical". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $154.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $50.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate* Credit towards follow-up repair Earliest Availability
Ford $154.99 $50.0
Toyota $154.99 $50.0
BMW $164.99 $50.0

*Estimates may vary by market

SCHEDULE P0778 DIAGNOSTIC Get a fair and transparent estimate upfront

P0778 code definition

The PCM stores the P0778 code when an abnormal voltage reading is detected from the electronic pressure control solenoid, or the correlating circuit.

What the P0778 code means

In order to operate the engine efficiently, the PCM monitors the fluid pressure from a variety of sensors within the engine. For every specific driving condition, there is a preset manufacturer specification that tells the PCM what the voltage reading should be to ensure optimal fluid pressure. If the pressure control solenoid does not report the proper voltage reading, the PCM assumes a problem with the engine fluid pressure, and stores the P0778 code.

What causes the P0778 code?

Common causes may include:

  • Faulty electronic pressure control solenoid B, or solenoid B valve
  • Blocked transmission fluid passages
  • Internal transmission failures
  • Low transmission fluid, or dirty or contaminated transmission fluid
  • Faulty electrical components within the pressure control solenoid B

What are the symptoms of the P0778 code?

The symptoms that can accompany the P0778 code can vary greatly. In addition to the illuminated Check Engine lamp, drivers may observe:

  • Inability to shift gears
  • Harsh shifting
  • Slipping transmission
  • Overheated transmission
  • Decreased fuel economy
  • Failure of the torque converter clutch to either engage or disengage

In addition, there may be other torque converter clutch, gear ratio, lock up, shift solenoid, or transmission slippage codes stored with the P0778 code.

How does a mechanic diagnose the P0778 code?

After an OBD-II scanner detects the P0778 code, there are two things that the technician should turn to first: a visual inspection of all electrical wiring, connectors, and harnesses, and a visual inspection of the transmission fluid. Any damaged or loose electrical components should be replaced; contaminated transmission fluid should be flushed, and the system should be refilled with clean fluid.

These are two very common and relatively inexpensive repairs that can cause this code. After these, and each subsequent repair, the mechanic should clear the PCM and retest the system. If the P0778 code returns, then the mechanic should begin testing the solenoid and other potentially faulty components, until the fault is found.

Common mistakes when diagnosing the P0778 code

The most common mistake made during the diagnostic process for the P0778 code is replacing the high pressure pump, rather than checking for faulty solenoids or wiring.

How serious is the P0778 code?

The P0778 code represents a serious drivability issue. Without the ability to monitor and actuate changes within the engine fluid pressure, the vehicle may not operate safely or optimally. It is important to have this repair done as soon as possible after detecting this code.

What repairs can fix the P0778 code?

Common repairs may include:

  • Replacing a faulty electronic pressure control solenoid B, or solenoid B valve.
  • Clearing and refilling blocked transmission fluid passages.
  • Addressing any internal transmission failures.
  • Refilling low transmission fluid, or replacing dirty or contaminated transmission fluid.
  • Repairing or replacing any faulty electrical components within the pressure control solenoid B.

Need help with a P0778 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P0778

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0778 code.

SCHEDULE P0778 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(8600)

Rating Summary
8017
273
65
46
199
8017
273
65
46
199
 at YourMechanic

Brandon

9 years of experience
133 reviews
Brandon
9 years of experience
Ford Escort L4-2.0L - Check Engine Light is on - Nashville, Tennessee
Brandon showed up ahead of schedule, was very personable and diagnosed my problems. He also scheduled my next appointments which will be with him.
 at YourMechanic

William

23 years of experience
33 reviews
William
23 years of experience
Lexus IS250 V6-2.5L - Check Engine Light is on - Mableton, Georgia
Arrived early which was great. William was courteous, and attentive to the issue. Even though it took several attempts I'm so happy he was determined to fix it and he did!
 at YourMechanic

Dan

40 years of experience
1080 reviews
Dan
40 years of experience
Plymouth Grand Voyager - Check Engine Light is on - Lawrenceville, Georgia
Mr. Dan Barber was quite patient, courteous and quite knowledgeable. From my observation, Mr. Barber appears to be quite professional.
 at YourMechanic

Christopher

9 years of experience
120 reviews
Christopher
9 years of experience
Ford Fiesta L4-1.6L - Check Engine Light is on - Smyrna, Georgia
Chris communicated with us each step of the way up until his arrival. He listened well, was knowledgeable, and was prepared. He took the time to diagnose the problem, explained the what, why and how and provided a solution. I would definitely recommend him and will use him again.


More related articles

Related questions

Gas pedal needs to be pressed down farther than normal before it works
The throttle pedal sensor and the throttle body sensor need to correlate to each other or the computer goes into limp mode and will not accelerate properly. A test to move the throttle body and throttle pedal position needs to...
Could this be the TCM causing the problem?
Yes, no start in the scenario you are describing is possible especially if Code U1000 has set, along with other codes such as P0717, but there are multiple code scenarios or combinations. One quick strategy is to pull and visually...
My 2001 chevy venture shuts off on me at random times . A couple of days the check engine light was on so we hooked the computer u
It's not unusual for code P0420 to come on, stay on for even a few days, and then just disappear. Then, months later, it might happen again (i.e., appear and disappear). If this is the circumstances you face, I would...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com