What Does P0748 Mean?
An electrical fault has been detected in pressure control solenoid A circuit. The PCM/TCM is reading abnormal voltage or current in the solenoid wiring, pointing to an open, short to ground, or short to power condition. Without proper electrical control, the solenoid cannot regulate transmission line pressure.
Common Causes
30%
Pressure control solenoid A internal electrical failure (open or shorted coil)
30%
Damaged wiring between TCM and solenoid (open, shorted, or high resistance)
20%
Corroded or damaged transmission connector pins
12%
TCM/PCM solenoid driver circuit failure
8%
Poor ground connection affecting solenoid circuit
Diagnostic Steps
1
Measure pressure control solenoid A resistance at the transmission connector — compare to specifications (typically 4-8 ohms for a variable force solenoid).
2
Inspect the transmission external connector for corrosion, water intrusion, bent pins, or damaged seals.
3
Perform a continuity and short-to-ground test on each wire in the PCS A circuit from the TCM to the transmission connector.
4
Verify TCM power and ground circuits are within specification — a poor ground can affect all solenoid circuits.
5
If wiring and solenoid test good, test the TCM solenoid driver output to rule out a failed controller.
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
An electrical fault has been detected in pressure control solenoid A circuit. The PCM/TCM is reading abnormal voltage or current in the solenoid wiring, pointing to an open, short to ground, or short to power condition. Without proper electrical control, the solenoid cannot regulate transmission lin...
The most common cause of P0748 (Pressure Control Solenoid A Electrical) is: Pressure control solenoid A internal electrical failure (open or shorted coil)
Typical repair costs for P0748 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The transmission will likely default to maximum line pressure (firm/harsh shifts) or enter limp mode. The vehicle can be driven cautiously for short distances but shift quality will be poor. Repair soon to prevent additional transmission wear.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0748 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission — Hydraulic Control
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
