P0748 on Hyundai: How to Diagnose & Fix
Pressure Control Solenoid "A" Electrical
1 Hyundai model · 1 documented issue · $600-$4,500 repair
P0748 on Hyundai by model: symptoms, diagnosis and fix
The A6-series six-speed automatic fitted to the YF and LF Sonata wears the aluminium bores that house the solenoid pressure-reducing valves. The worn bores leak line pressure internally, so clutch apply pressure falls and the transmission either flares (RPM jumping between gears as a clutch slips) or bangs into gear once the pressure command finally builds. Reports of the wear appearing by 40,000-60,000 miles are common. Symptoms are frequently misdiagnosed as a bad solenoid pack and the solenoids replaced without addressing the bores, which returns the fault within months. This is distinct from the wet dual-clutch (DCT) shudder complaint on the turbo and hybrid variants - the A6MF is a conventional torque-converter automatic.
Common Symptoms
- Engine RPM flares between upshifts
- Harsh or banging 1-2 and 2-3 shifts
- Delayed engagement into drive or reverse
- Slipping under light throttle
- Intermittent stuck in one gear / limp mode
- Check engine light with transmission pressure codes
How to Fix
The durable repair is a valve body rebuild with an oversized valve kit (Sonnax-style) to restore the worn bores, or a replacement valve body - roughly $600-1,400 installed, versus $2,500-4,500 for a full transmission replacement. Start by scanning for pressure-control codes and checking fluid level and condition on a warm engine; some early-stage cases improve with a proper SP-IV fluid service and a TCU relearn, but that is a delay not a cure. Have the shop specifically confirm bore wear before agreeing to a solenoid-only repair. No recall covers this; some cars were repaired under the 10-year/100,000-mile powertrain warranty for original owners.
Sources for this issue (3)
P0748 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0748 mean on a Hyundai?
P0748 stands for "Pressure Control Solenoid "A" Electrical." P0748 is a generic powertrain code meaning the transmission control module has detected an electrical fault — voltage or resistance out of the expected range — in the circuit for pressure control solenoid "A". This solenoid regulates hydraulic line pressure inside an automatic transmission, adjusting how firmly the clutches and bands apply based on speed, load, and throttle position. When the computer can't control the solenoid electrically, the transmission often defaults to maximum line pressure or limp mode, so you may feel harsh or erratic shifts, slipping, delayed engagement when shifting into Drive, or being locked into a single gear. Because it is an electrical-circuit code, the fault is usually in the solenoid itself or its wiring rather than a purely hydraulic problem, though contaminated fluid can damage the solenoid. Continuing to drive with slipping and overpressure shifts can overheat the transmission and lead to expensive internal damage, so this should be repaired promptly. On Hyundai it is documented across 1 model: Sonata.
What are the most common causes of P0748?
The most common causes of P0748 are: Failed pressure control solenoid A (open or shorted solenoid windings), Damaged, frayed, or shorted wiring in the solenoid circuit, including the transmission case connector, Corroded or loose electrical connectors at the transmission harness, Low, dirty, or contaminated transmission fluid degrading or sticking the solenoid, Clogged transmission filter or debris in the valve body hydraulic passages, Faulty transmission control module or PCM driver circuit (rare). The specific cause varies by vehicle.
How much does it cost to fix P0748 on a Hyundai?
Published repair estimates on Hyundai range from $600 to $4,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0748 on a different make?
View P0748 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.