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

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0778 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars 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 $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 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$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0778 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

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.

P0778
trouble codes
Check Engine Light

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0778 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,526

Rating Summary
3,215
155
41
23
92
3,215
155
41
23
92

Chris

19 years of experience
1240 reviews
Chris
19 years of experience
On time, diagnosed my car and I made an apt. for him to come back and do the work. Good prices too.
1997 CHRYSLER SEBRING - CHECK ENGINE LIGHT IS ON - LAGUNA HILLS, CALIFORNIA

Eric

9 years of experience
222 reviews
Eric
9 years of experience
Favorably over 30 minutes early for appointment. Polite, personable, professional. Highly knowledgeable. Answered questions and explained process, problem, etc. effectively.
2007 NISSAN MURANO - CHECK ENGINE LIGHT IS ON - RALEIGH, NORTH CAROLINA

Peter

40 years of experience
1059 reviews
Peter
40 years of experience
Was able to come earlier than scheduled. He determined that part of the ensuing repair would require a software update from the dealer and assisted in providing the information needed for the dealer tech to find the software upgrade in their system so they could install it. Excellent!
2007 DODGE RAM 1500 - CHECK ENGINE LIGHT IS ON - SUN CITY, ARIZONA

Tabitha

14 years of experience
106 reviews
Tabitha
14 years of experience
I'm very pleased with the results. My car is running smoothly! I will look forward to my next services, tune up, with my mechanic Tabitha. Thanks for taking care of my car.
2012 FORD FIESTA - CHECK ENGINE LIGHT IS ON - SAN DIEGO, CALIFORNIA

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...
P0291OBD-II Trouble Code: Cylinder 11 Injector Circuit Low
P0291 code definition When your vehicle’s PCM registers the P0291 code, it means that a voltage reading came from the fuel injector circuit – for cylinder number 11’s fuel injector –...

Related questions

Q: The engine light is blinking, the car jolts when it car accelerates. And the engine songs like it wants to shut off sometimes

The flashing Check Engine Light tells me that the engine is having a misfire condition occurring. This could be due to bad spark plugs or ignition coils as well as other sensor on the engine reading incorrectly. There will be...

Q: I just had water pump replaced and I'm having issues.

Hello. It sounds like something was not reinstalled correctly. The fact that the Check Engine Light is flashing tells me that there is an engine misfire. This can be caused by a loose connection or it may be something that...

Q: P0089 code, fuel pressure regulator performance low. Went into limp mode, then next morning no start

After doing a little research on your particular situation, it looks as though this is a fairly common problem with this model of vehicle. I would suggest contacting your local dealership about the situation due to the fact that I...

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.

1-800-701-6230 · hi@yourmechanic.com