P0748 on Kia: How to Diagnose & Fix
Pressure Control Solenoid "A" Electrical
2 Kia models · 2 documented issues · $400-$2,200 repair
P0748 on Kia by model: symptoms, diagnosis and fix
The YD-generation Forte's conventional six-speed automatic (A6GF1 behind the 1.8/2.0 Nu, A6MF2 behind the 1.6T) wears the aluminium valve-body bores that carry the two pressure-reducing valves and the torque-converter-clutch control valve. As the bores egg out, solenoid feed pressure becomes unstable: line pressure control goes off, upshifts flare or momentarily neutral, the 6-4 kickdown lands as a bang, and torque-converter lockup applies harshly or shudders at light throttle around 40-50 mph. It sets TCC-circuit and pressure codes rather than a hard failure code. This is a hydraulic wear failure of the torque-converter automatic and must not be confused with the BD-generation IVT judder or the GT's 7-speed dry DCT shudder - three different transmissions with three different failure mechanisms.
Common Symptoms
- Hard bang on 6-4 kickdown
- Flare or momentary neutral between upshifts
- Shudder or vibration at light throttle 40-50 mph as lockup applies
- Delayed engagement into Drive or Reverse
- Erratic shift points and slipping under load
How to Fix
Start with a genuine Kia SP-IV fluid exchange (not a high-pressure flush) - degraded fluid accelerates bore wear and sometimes quiets an early shudder. The durable fix is valve-body service: either a remanufactured/OEM valve body, or a bore-repair kit (TransGo SK A6MF and equivalents) that re-sleeves the reducing-valve and TCC control-valve bores. A P0743 almost always means the TCC solenoid itself, which Kia addressed in a transmission TSB. If lockup shudder is severe and long-standing, replace the torque converter with the valve body or the shudder returns. No recall covers this.
Sources for this issue (4)
- TransGo A6MF1/2, A6GF1, A6LF1/2/3 Shift Kit valve body repair kit - documented failure modesarticle
- P0743 Torque Converter Clutch solenoid on A6GF1 - Kia TSB TSBTRA051R1 referencearticle
- 2014-2016 Kia Forte 1.6L Turbo A6MF2 Transmission: Problems and Identificationarticle
- Kia Forte Service Manual - Torque Converter Control Solenoid Valve (T/CON_VFS) Removalarticle
The A6MF-family 6-speed automatic can develop harsh or erratic shifting, hard 6-to-4 kickdown 'bang,' shift flares, brief neutral feel during up/downshifts, and torque-converter clutch (TCC) shudder. The root cause is wear of the reducing-valve bores in the valve body, which lets line pressure drift out of spec; neglected fluid (SP4-spec) accelerates the wear. A documented secondary fault is a valve-body bolt that can abrade the internal wiring harness, producing intermittent solenoid faults. This is a distinct transmission failure mode from the AWD rear-differential coupling noise already documented.
Common Symptoms
- Hard or jerky shifts
- 6-to-4 downshift bang/clunk
- RPM flare or neutral feeling between shifts
- Torque-converter shudder at light cruise
- Delayed engagement into Drive/Reverse
How to Fix
Start with a proper SP4-spec fluid service and a TCM software update if available. Persistent harsh shifting, gear-ratio or solenoid-performance codes are usually resolved by rebuilding or replacing the valve body (with the reducing valves/solenoids), and inspecting the internal harness for abrasion. In severe slip/shudder cases the torque converter is replaced.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Kia UM013-CH059 ATF Type 4(M) / SP-IV transmission fluidOEMKia UM013-CH059
Use only for a Kia-procedure fluid service after level, condition and transmission diagnosis Fitment/availability: 2017-2022 Kia Sportage QL six-speed automatic, both 2.4L GDI and 2.0L T-GDI; the current Kia guide lists total fill 7.1 qt…
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Sources for this issue (2)
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 Kia?
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 Kia it is documented across 2 models: Forte, Sportage.
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 Kia?
Published repair estimates on Kia range from $400 to $2,200 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.