Skip the auto shop - Our mechanics make house calls

P0779 OBD-II Trouble Code: Pressure Control Solenoid B Intermittent

Check Engine Light

P0779 OBD-II Trouble Code: Pressure Control Solenoid B Intermittent

P0779 Code Definition

The P0779 code is a generic powertrain code related to the transmission, including sensor failures and pressure faults. In this case, the engine control module (ECM) has detected a fault with Pressure Control Solenoid B, receiving intermittent voltage signals.

Codes related to the P0779 include:

What the P0779 Code Means

The automatic transmission is controlled by the ECM with varying degrees of hydraulic pressure, which provides shift actuation and torque converter lock up. Utilizing electronic pressure control solenoids, which are controlled by the ECM, the hydraulic pressure is regulated.

The parameters for which a P0779 code can be set varies by each automaker, so check your service manual for specifics for your vehicle’s make and model. However, typically the ECM utilizes calculations from several sensors, including the pressure control sensor, to determine how much pump pressure is needed for operation. When the transmission fluid pressure doesn’t match the amount the ECM detects, a P0779 code can be stored.

What Causes the P0779 Code?

Several problems may cause a P0779 code including:

  • Low transmission fluid
  • Dirty or contaminated transmission fluid
  • Damaged or defective electronic pressure control solenoid
  • Hydraulic blockage inside transmission fluid passages
  • Transmission failure
  • Damaged or defective transmission control module
  • Damaged or defective ECM (rare)

What are the Symptoms of the P0779 Code?

Symptoms of a P0779 code may include:

  • Check Engine or Warning Light may illuminate
  • There may be no discernable symptoms for a P0779 code
  • The torque converter clutch may not engage
  • The torque converter clutch may not disengage
  • The vehicle may shift roughly
  • The vehicle may not shift in or out of gear (including park)
  • Decreased fuel economy
  • The transmission may overheat
  • You may experience transmission slippage
  • The transmission may enter “limp” mode

How Does a Mechanic Diagnose the P0779 Code?

A mechanic may use several methods to diagnose a P0779 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored P0779 trouble code
  • Check transmission fluid level
  • Check transmission fluid quality
  • If transmission fluid is dirty, check transmission pan for contamination and debris
  • Check related wiring and circuitry for damage or corrosion
  • Check for any transmission fluid leaks
  • Use a manual pressure gauge to check transmission pump pressure
  • Check for clogged hydraulic passages
  • Check for reference voltage and ground signals at electronic pressure control solenoid B
  • Use a digital volt/ohmmeter to check all circuits for continuity and resistance

Common Mistakes when Diagnosing the P0779 Code

At times, a high pressure pump may be replaced in oversight of a faulty electronic pressure control solenoid or damaged or malfunctioning wiring. It is recommended to test all system circuitry and repair any damage within before replacing the high pressure pump.

How Serious is the P0779 Code?

Because a vehicle’s safe driving operation most likely will be impacted due to faults that store a P0779 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What Repairs can Fix the P0779 Code?

Several repairs can fix a P0779 trouble code and include:

Need Help with a P0779 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...


Related questions

Q: My speedometer is going back and fourth and drops to zero while driving but, my rpm gauge is fine.

Hello. The crankshaft position sensor will not cause a fluctuation in the speedometer gauge. It can affect the rpm gauge, but not the speedometer. If the speedometer is acting like this then most of the time this is caused by...

Q: I have a 2009 VW Jetta S 2.5L. Why does my car turns on but then it turns off after driving it for a bit/while?

These are the following definitions for the codes you've received: P0864 - Transmission control module (TCM) communication circuit -range/performance problem P0070 - Ambient Air Temperature Sensor - (possibly shorted but most likely not related) P0734 - Gear 4 Incorrect...

Q: I believe one of my ignition coils is bad, how can I test to see which one is bad?

The only way to determine exactly which ignition coil is damaged is to have a professional mechanic complete a diagnostic scan and download all error codes. The OBD-II error codes will pinpoint the source of engine issues. Having a mechanic...