Pressure control solenoid A sets line or clutch pressure by current; most are 'normally high', so with no current – as in limp mode – maximum pressure applies. 'A' is usually the line pressure valve, on GM clutch-to-clutch transmissions (6T, 8L, 9T) the pressure valve of clutch 1. Ford does not use P0745–P0749 but P0960–P0963. P0748 is the electrical code of this valve, checked by current, duty cycle or terminal voltage: Subaru after 0.14 s with MIL after two trips and limp mode in third, Allison against an 8 Ω current model after 125 ms, GM's diesel 4L80-E for a duty cycle outside 0.5–95 % for 2 s without MIL. The valve is switched off – maximum pressure, harsh shifts, frozen adaption, often a fixed gear (Saab AF40: second and reverse) and reduced torque. Saab's 2010 9-5 uses P0748 for a current deviation instead.
Medium severity. Can I keep driving?Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
Symptoms
- Harsh shifts or engagement (maximum pressure)
- Limp mode in a fixed gear
- Transmission warning or check engine light
- Reduced engine power (torque limit)
Most likely causes
- Harness or transmission connector (corrosion, oil, chafing)
- Pressure control solenoid faulty (resistance out of spec)
- Internal harness, electronic module or mechatronic unit
- System voltage too low
- Transmission module driver
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P0748 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 7: Transmission
- 48: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0748?
Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
What causes code P0748?
The most common causes are: harness or transmission connector (corrosion, oil, chafing); pressure control solenoid faulty (resistance out of spec); internal harness, electronic module or mechatronic unit.
Related codes
- P0745Pressure Control Solenoid A
- P0746Pressure Control Solenoid A Performance/Stuck Off
- P0747Pressure Control Solenoid A Stuck On
- P0749Pressure Control Solenoid A Intermittent
- P0962Pressure Control Solenoid A Control Circuit Low
- P0963Pressure Control Solenoid A Control Circuit High
Sources
- saabwisonline.com: dtc p0748 pressure control solenoid a electrical
- gsi.ext.gm.com: 2006trans9
- gsi.ext.gm.com: 2006trans5 a
- gsi.ext.gm.com: 2006trans11
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.