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Summary
  • The P0748 code stands for “Pressure Control Solenoid ‘A’ Electrical.” 
  • It’s triggered when the PCM detects complications in the pressure control solenoid that is designated “A.”
  • A defective or faulty pressure control solenoid is one of the common triggers for the code.
  • Erratic shifting and poor fuel economy are two common symptoms to look out for.

Electronically controlled automatic transmissions have a pressure control solenoid that controls the transmission’s hydraulic pressure. needed to make the transmission operate properly. If your powertrain control module (PCM) detects problems in your pressure control solenoids, it may trigger trouble codes, including code P0748.

If a P0748 code pops up after using a scan tool, you need to get your vehicle fixed soon to avoid additional issues. Here’s what you need to know about the P0748 code:

What Does the P0748 Code Mean?

Diagnostic trouble code (DTC) P0748 stands for  “Pressure Control Solenoid ‘A’ Electrical.”  This code is generally set by your PCM if it detects complications in the pressure control solenoid that is designated “A.” The electronic automatic transmission’s pressure control solenoid(s) regulate transmission hydraulic pressure in response to throttle angle, engine speed, and prevailing load requirements.

See also  P0752 Code: Shift Solenoid “A” Stuck On

For example, if you’re pulling a trailer up a hill, the ECM/PCM will increase transmission line pressure to hold the gears longer and provide a firmer shift, because that’s what’s needed under those circumstances. If you aggressively accelerate even on flat pavement, the same command is delivered.

pressure control solenoid circuit schematic
The illustration shows a basic pressure control solenoid circuit. Typically if there are “A” and “B” PC solenoids, there will obviously be more than one pressure control solenoid. | Image Source: Richard McCuistian

Transmission line pressure determines shift timing and quality and if the electrical circuit controlling the Pressure Control Solenoid fails the line pressure will default to maximum. The transmission will usually shift much firmer and it may also shift later, depending on the platform. The firm shift protects the clutches to prevent them from burning out, which happens if they’re not firmly applied and the transmission is providing torque to the output.

“Electrical” indicates that this is a problem with the circuit rather than the mechanical part of the solenoid itself, although the solenoid winding may be the cause of the fault code.

Note: The definition of code P0748 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0748 Code?

A P0748 code can be triggered by various vehicle problems. Here are this trouble code’s most common causes:

  • Defective or faulty pressure control solenoid
  • Dirty transmission filter and/or fluid
  • Faulty transmission pump and/or valve body
  • Clogged hydraulic channels
  • Wiring or connector damage
  • PCM malfunction or damage

What are the Common Symptoms of the P0748 Code?

Trouble codes can be accompanied by different symptoms. They can change depending on what is causing the P0748 code. Here are the most common symptoms of a P0748 code:

See also  P0770 Code: Shift Solenoid "E" Malfunction

How to Diagnose the P0748 Code

Like all trouble codes, P0748 can become difficult to diagnose. Diagnosis and troubleshooting can also vary, depending on your vehicle’s make and model. Consulting a professional is the quickest way to fix issues causing your vehicle’s P0748 code. However, you can get a good idea of how to diagnose this trouble code by watching this video:

How to Fix the P0748 Code

Problems that cause trouble codes may not be a big deal at first. However, they can become severe over time. You can try working on a P0748 code from home, but fixing trouble codes can be too technical for a DIYer. Asking a mechanic for help is the fastest way to fix the P0748 code.

You can get an understanding of the P0748 code by doing some research. First, you can determine what’s causing the code and the complications related to it. Once you have all the information, you need to check a reliable repair manual or online repair database to work out the correct course of action.

See also  P0751 Code: Shift Solenoid “A” Performance/Stuck Off

It is also a good idea to have your vehicle’s repair manual on hand. Some fixes that work on other vehicles may not work for yours. What applies for a P0748 code in a Dodge may not apply for a Ford. Tread carefully as you try to resolve your vehicle’s problems. If it becomes too difficult to do on your own, don’t think twice about asking a mechanic for help.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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