AutoCodes – Buick – P0748 Buick

P0748 Buick Code - Pressure Control Solenoid Circuit Electrical

Quick Answer

The Pressure Control (PC) solenoid valve is an electronic device that regulates transmission line pressure based on the current flow through its coil winding. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Pressure Control Solenoid. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0748 Buick indicates Pressure Control Solenoid Circuit Electrical.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Pressure Control Solenoid.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 7,942

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jan 29, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0748 Buick Description

The Pressure Control (PC) solenoid valve is an electronic device that regulates transmission line pressure based on the current flow through its coil winding. The magnetic field produced by the coil moves the solenoid's internal valve which varies pressure to the pressure regulator valve. The Powertrain Control Module (PCM) controls the PC solenoid valve by applying a varying amount of amperage to the solenoid. The applied amperage can vary from 0.1 to 1.1 amps. Low amperage (0.1 amp) indicates high line pressure. High amperage (1.1 amps) indicates low line pressure. The duty cycle of the PC solenoid valve is expressed as a percentage of energized ON time. Zero percent indicates zero ON time (non-energized) or no current flow. Approximately 60% at idle indicates maximum ON time (energized) or high current flow. The PCM determines the appropriate line pressure for a given load by comparing the throttle position (TP) voltage, the engine speed and other inputs.

OBDII Code P0748 Buick - Pressure Control Solenoid Circuit Electrical - AutoCodes.com — P0748 Buick Code - Pressure Control Solenoid Circuit Electrical

What does this mean?

What are the Possible Causes of the DTC P0748 Buick?

Low transmission fluid level
Dirty transmission fluid
Faulty Pressure Control Solenoid
Pressure Control Solenoid harness is open or shorted
Pressure Control Solenoid circuit poor electrical connection

How to Fix the DTC P0748 Buick?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

When a transmission solenoid is malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure and that the transmission will need to be rebuilt or replaced.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0748 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.