P0748 Pressure control solenoid valve A electrical

OBD-II Trouble Code - P0748 - Data Sheet

P0748 - Pressure control solenoid valve A, electrical.

This code stands for Electric Pressure Control Solenoid. This code may have a different definition for some vehicle brands, so be sure to check the specific codes for your vehicle.

What does trouble code P0748 mean?

This is a Generic Transmission Diagnostic Trouble Code (DTC) and is commonly applied to OBD-II vehicles equipped with an automatic transmission.

This may include, but is not limited to, Ford, Mercury, Lincoln, Jaguar, Chevrolet, Toyota, Nissan, Allison / Duramax, Dodge, Jeep, Honda, Acura, etc. While general, exact repair steps may vary depending on from the year. , make, model and equipment of the power unit.

When the P0748 OBD-II DTC is set, the powertrain control module (PCM) detected a problem with the transmission pressure control solenoid "A". Most automatic transmissions have at least three solenoids, which are solenoids A, B, and C. Trouble codes associated with solenoid "A" are P0745, P0746, P0747, P0748, and P0749. The code set is based on a specific fault that alerts the PCM and turns on the check engine light.

The transmission pressure control solenoid valves control fluid pressure for proper automatic transmission operation. The PCM receives an electronic signal based on the pressure inside the solenoids. The automatic transmission is controlled by belts and clutches that shift gears by applying fluid pressure to the right place at the right time. Based on signals from associated vehicle speed control devices, the PCM controls the pressure solenoids to direct fluid at the appropriate pressure to various hydraulic circuits that change the transmission ratio at the right time.

P0748 is set by the PCM when the "A" pressure control solenoid experiences an electrical fault.

Example of a transmission pressure control solenoid:

What is the severity of this DTC?

The severity of this code usually starts at moderate, but can quickly progress to a more serious level if not corrected in a timely manner.

What are some symptoms of code P0748?

If this code is stored, you may not notice any obvious symptoms, or you may notice serious shifting problems, such as no shift at all. The engine may stall at idle, gear shifts may be harsh or slip, and the transmission may overheat. Other symptoms include reduced fuel economy and a malfunction indicator light (MIL) on. Other codes may be set, such as those related to gear ratio, shift solenoids, or transmission slip.

Symptoms of a P0748 trouble code may include:

• The car goes into emergency mode
• Transmission slips when shifting gears
• Overheating of the transmission
• Transmission stuck in gear
• Reduced fuel economy
• Possible misfire-like symptoms
• Check Engine light is on

What are some of the common causes for the code?

The pressure control solenoid valve may fail if any of the following conditions are present:

• Contaminated or dirty transmission fluid
• Liquid with low throughput
• Hydraulic blockages in transmission fluid passages
• Bad electronic pressure control valve
• Mechanical internal transmission error
• Defective TCM (Transmission Control Module)
• Defective PCM (rare)
• Defective pressure control solenoid
• Dirty or contaminated liquid
• Dirty or clogged transmission filter
• Defective transmission pump
• Defective transmission valve body
• Limited hydraulic passages
• Corroded or damaged connector
• Faulty or damaged wiring
• Defective PCM

What are some steps to troubleshoot the P0748?

Before beginning the troubleshooting process for any problem, you should review the vehicle-specific Technical Service Bulletins (TSB) by year, model and transmission. In some cases, this can save you a lot of time in the long run by pointing you in the right direction. You should also check the vehicle records to check when the filter and fluid were last changed, if possible.

Checking fluid and wiring

The first step is to check the fluid level and check the condition of the fluid for contamination. Before changing the fluid, you should check the vehicle records to find out when the filter and fluid were last changed.

This is followed by a detailed visual inspection to check the condition of the wiring for obvious defects. Check connectors and connections for safety, corrosion and damage to pins. This should include all wiring and connectors to the transmission pressure control solenoids, transmission pump, and PCM. The transmission pump can be electrically or mechanically driven, depending on the configuration.

Advanced steps

Additional steps are always vehicle specific and require appropriate advanced equipment to be performed accurately. These procedures require a digital multimeter and vehicle-specific technical reference documents. You should receive specific troubleshooting instructions for your vehicle before proceeding with the advanced steps. Voltage requirements can vary greatly from vehicle model to vehicle. Fluid pressure requirements will also vary based on transmission design and configuration.

Continuity checks

Unless otherwise specified in the datasheet, normal wiring and connection readings should be 0 ohms of resistance. Continuity checks should always be performed with circuit power disconnected to avoid short circuiting the circuit and causing more damage. Resistance or no continuity indicates faulty wiring that is open or shorted and requires repair or replacement.

What are the standard ways to fix this code?

• Replacing fluid and filter
• Replace defective pressure control solenoid.
• Repair or replace a faulty transmission pump
• Repair or replace a faulty transmission valve body
• Flushing transmission for clean passages
• Cleaning connectors from corrosion
• Repair or replacement of wiring
• Flashing or replacing PCM

Possible misdiagnosis may include:

• Engine misfire problem
• Transmission pump problem
• Internal transmission problem
• Transmission problem

Hopefully the information in this article has helped point you in the right direction for solving your pressure control solenoid DTC problem. This article is for informational purposes only and specific technical data and service bulletins for your vehicle should always take priority.

COMMON ERRORS WHEN DIAGNOSING CODE P0748

Often this malfunction is declared a misfire problem in the engine or the high pressure pump is considered the culprit. Wiring and other circuits involved may be overlooked as possible causes. It is important to ensure that the complete diagnostic process is carried out.

HOW SERIOUS CODE P0748 IS?

Transmission problems should always be fixed as soon as possible. Even if the problem has not progressed to the point where an internal mechanical failure has occurred, the onset of symptoms means there is a problem that can become serious in a very short time.

WHAT REPAIRS CAN FIX CODE P0748?

Possible fixes for this error code include:

• Repair of pressure control circuits such as wiring and connectors
• Pressure Regulator Solenoid Replacement
• Replacing the electronic pressure regulator
• Restoration or replacement of the entire gearbox, including the torque converter.
• Flushing and changing transmission fluid
• Replacement of TSM

ADDITIONAL COMMENTS REGARDING CODE P0748 CONSIDERATION

Checking the condition of the transmission oil is an important step in troubleshooting a transmission. If the fluid looks or smells burnt, or has a dark, opaque color, the vehicle is almost certainly running with a low fluid level. This means that catastrophic internal damage may have already occurred.

Although some parts of the diagnostic process can be done at home, such as B. Transmission fluid assessment (if you have a dipstick). It is better to contact a qualified specialist as soon as possible.

How to Diagnose and Fix P0748 Engine Code - OBD II Trouble Code Explain

Need more help with the P0748 code?

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.