Faulty pressure control solenoid A itself, such as a burned coil or stuck valve; Damaged or corroded wiring harness or connector at the transmission solenoid pack; Transmission fluid contaminated with debris or degraded, causing solenoid blockage; Internal transmission valve body wear or sticking valves affecting solenoid operation; Failed transmission control module (TCM) or poor ground connection; Low transmission fluid level due to a leak

DTC codes / Mazda codes / P1748

P1748 · MazdaPressure Control Solenoid A

Q: What does code P1748 mean?

Pressure Control Solenoid A. P1748 on Mazda vehicles indicates that the transmission control module (TCM) has detected an electrical fault in the pressure control solenoid A circuit, which regulates hydraulic pressure inside the automatic transmission. The TCM monitors the solenoid's current draw and response, and when the signal falls outside the expected range, it stores this code and typically illuminates the warning light.

P1748 on Mazda vehicles indicates that the transmission control module (TCM) has detected an electrical fault in the pressure control solenoid A circuit, which regulates hydraulic pressure inside the automatic transmission. The TCM monitors the solenoid's current draw and response, and when the signal falls outside the expected range, it stores this code and typically illuminates the warning light.

SystemPowertrain

Code typeMazda specific

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

Harsh or delayed gear shifts, especially when engaging drive or reverse
Transmission slipping or flaring between gears
The vehicle entering limp mode with reduced power and limited gear selection
A noticeable thump or jerk when shifting from park to drive
Often no symptoms besides the warning light, especially in early stages

Common causes, most likely first

Faulty pressure control solenoid A itself, such as a burned coil or stuck valve
Damaged or corroded wiring harness or connector at the transmission solenoid pack
Transmission fluid contaminated with debris or degraded, causing solenoid blockage
Internal transmission valve body wear or sticking valves affecting solenoid operation
Failed transmission control module (TCM) or poor ground connection
Low transmission fluid level due to a leak

How to diagnose and fix it

Check transmission fluid level and condition; top up or replace if contaminated
Inspect the solenoid wiring harness and connector for damage, corrosion, or loose pins
Measure the resistance of pressure control solenoid A and compare to Mazda specifications
Perform a voltage drop test on the solenoid circuit to rule out wiring resistance
If resistance is out of spec, replace the solenoid and clear the code
If the solenoid tests good, inspect the valve body for sticking valves or debris
After repair, clear codes and perform a relearn or adaptation drive cycle as required

Don't replace the solenoid before checking these

A dirty or degraded transmission fluid is a frequent culprit that mimics a failed solenoid, so a fluid service often resolves the issue without parts replacement.
The wiring harness connector at the transmission is exposed to heat and vibration, and a loose pin or chafed wire can set P1748 even when the solenoid is healthy.
On some Mazda models, a weak battery or charging system can cause the TCM to log false solenoid codes, so verify battery voltage and grounds first.
P1748 can be stored intermittently due to a sticking valve body, which may not show up during a simple resistance test.
Replacing the solenoid without clearing the TCM adaptive memory can cause the new part to learn incorrectly and set the code again.

Can I keep driving with P1748?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration or heavy towing because the transmission may shift harshly or slip. If the vehicle enters limp mode or shifting becomes erratic, stop driving and have it towed to prevent further transmission damage.

Tools that help

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Guidance is general and written for Mazda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.