Skip the auto shop - Our mechanics make house calls

P0748 OBD-II Trouble Code: Pressure Control Solenoid Electrical

Check Engine Light

P0748 code definition

This code stands for Pressure Control Solenoid Electrical. In some vehicle makes, this code may have a different definition, so be sure to check on the specific for your vehicle.

What the P0748 code means

The pressure control solenoid manages transmission line pressure by monitoring various driving conditions such as speed, engine load, and throttle position. It sends messages to the vehicle’s computer in order to facilitate the appropriate pressure for those specific conditions. Signals are sent in the form of voltage readings, and if these readings indicate fluid pressure which does not match the expected measurements, this code will set.

What causes the P0748 code?

The pressure control solenoid electrical may set an error if any of the following conditions exist:

  • Contaminated or dirty transmission fluid
  • Low transmission fluid
  • Hydraulic clogs inside the transmission fluid passageways
  • A bad electronic pressure control solenoid
  • Mechanical internal transmission failure
  • A faulty TCM (transmission control module)
  • A faulty PCM (rarely)

What are the symptoms of the P0748 code?

If this code is stored you may not notice any discernible symptoms, or you may notice severe shifting problems such as a lack of shifting altogether. The engine may stall at idle, shifting may be harsh or there could be slippage, or the transmission could overheat. Other signs include decreased fuel economy and a lit malfunction indicator lamp (MIL). Other codes may set, such as those related to gear ratio, shift solenoids, or transmission slippage.

How does a mechanic diagnose the P0748 code?

Identifying the source of this error may include:

  • Verifying the stored code(s) and recording data with a scanner hooked up to the vehicle’s computer

  • Monitoring the scanner while driving to check whether the PCM is commanding the pressure control solenoid

  • Checking the transmission fluid level and condition

  • Visually inspecting the wiring and connectors for damage like corrosion or breaks

  • Performing pinpoint tests such as voltage and continuity tests on the pressure control solenoid circuit

  • Using a pressure gauge to measure the solenoid’s function

  • Removing the transmission pan to check for metal shavings or debris which indicate that internal mechanical transmission failure has begun

Common mistakes when diagnosing the P0748 code

It’s not uncommon for this error to be chalked up to an engine misfire issue, or to assume that the high pressure pump is the culprit. Wiring and other involved circuitry may be overlooked as possible causes. It’s important to make sure that a complete diagnostic process is carried out.

How serious is the P0748 code?

Transmission issues should always be addressed as quickly as possible. Even if the problem has not advanced to the point that internal mechanical failure has occurred, experiencing symptoms means that there is an issue which could become serious in very short order.

What repairs can fix the P0748 code?

Possible fixes for this DTC include:

Additional comments for consideration regarding the P0748 code

Checking the transmission fluid condition is a crucial step in rectifying any transmission-related error. If the fluid appears or smells burned or is a dark, opaque color, it is almost a certainty that the vehicle has been operated at a low fluid level. This means that catastrophic internal damage may have already occurred.

While some parts of the diagnostic process may be done at home, such as assessing the transmission fluid (if you have a dipstick), transmissions are not typically the kind of project you want to do in the driveway. It’s best to consult a qualified professional as soon as possible.

Need help with a P0748 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

The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: Problem starting after fueling have to give it to start

Hello. All modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the...

Q: After a timing belt replacement malfunction an indicator light has come on.

Hi there. I completely understand your concern. Could it simply be coincidence? Absolutely. Could it have been caused by an incorrect timing belt installation? It sure could. A Check Engine Light means that a malfunction has been detected and set...

Q: Trouble code P2015. I don't know how to fix it.

The intake manifold runner control is a system that controls amount of air entering the engine, by way of valves in each intake manifold runner. They are linked together as 4 per side, bank 1 and bank 2. The control...