P0748 on 2012-2014 Kia Soul: Pressure Control Solenoid 'A' Electrical Fault Guide

What's Unique About the 2012-2014 Kia SOUL

For this generation of Kia Soul with the 6-speed automatic (A6MF1/A6GF1 family), this code is a well-documented issue. Kia released a Technical Service Bulletin (TSBTRA051R1) specifically advising technicians to replace the faulty solenoid(s) if this code appears, and explicitly warning *not* to replace the entire transaxle assembly. This suggests the solenoid itself is a known failure point, saving owners from a much more expensive and unnecessary repair. This issue is common across a wide range of Hyundai and Kia vehicles that share this transmission.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: This range covers the first generation (2012-2013) and the second generation (2014) of the Kia Soul. Both generations used a 6-speed automatic transmission (A6MF1/A6GF1 family) that is known to experience this issue. The provided TSB applies to the transmission family, making the advice relevant across these model years and many other Hyundai/Kia models.

Symptoms You May Notice

• Check Engine Light is on
• Harsh, erratic, or delayed gear shifts
• Vehicle is stuck in one gear (usually 3rd gear, known as 'limp mode')
• Vehicle stalls when coming to a stop
• Noticeable decrease in fuel economy
• Transmission may feel like it's slipping or flaring between gears
• Loud clunk or tranck when shifting into Reverse

Most Likely Causes

1. Failed Pressure Control Solenoid 'A' 🔴 High Probability → Shop Transmission Valve Body This is a known failure point acknowledged by Kia's own Technical Service Bulletin (TSBTRA051R1). The solenoid's internal coil can burn out or fail due to heat and age. It is a common failure on the A6MF1/A6GF1 transmission family.
   How to confirm: After removing the transmission pan and valve body, the solenoid can be tested with a multimeter for resistance. The specification is typically around 5.0-5.6 ohms at 68°F (20°C). An open circuit (infinite resistance) or a reading far outside this range confirms failure. One can also apply 9V or 12V to the solenoid and listen for a solid 'click'.
   Typical fix: Replace the faulty solenoid. It is often recommended to replace the entire set of 8 solenoids as a kit while the valve body is removed, as they are all of the same age and prone to similar failure.
   Est. part cost: $50-$100 for a single solenoid, $90-$200 for a full 8-solenoid kit.
2. Damaged Internal Transmission Wiring Harness 🟡 Medium Probability → Shop Transmission Assembly The flexible ribbon-style harness inside the transmission is exposed to constant heat and fluid, and can become brittle and crack over time, causing an open or short circuit. This is a very common failure point and often occurs with the solenoid.
   How to confirm: Visually inspect the harness for cracks or damage once the valve body is removed. Perform a continuity test on the wire leading to solenoid 'A' from the main connector pins.
   Typical fix: Replace the internal wiring harness. This is often done at the same time as the solenoid replacement as a preventative measure. The harness often includes a new transmission temperature sensor, which is another common failure item.
   Est. part cost: $70-$150
3. Low or Contaminated Transmission Fluid 🟡 Medium Probability → Shop Transmission Assembly Low fluid can cause pressure drops and overheating, stressing electrical components like solenoids. Dirty fluid can cause solenoids to stick or clog, leading to electrical faults. These transmissions are 'sealed for life' and lack a dipstick, making fluid level checks less common for the average owner.
   How to confirm: Check the transmission fluid level and condition via the fill plug on the side of the case. This must be done with the vehicle level and at a specific operating temperature. The fluid should be pink/red in color and not smell burnt.
   Typical fix: Perform a transmission fluid drain-and-fill with fluid meeting the Kia SP-IV specification. If the fluid is very dark or has metal shavings, more serious internal damage is likely. 🎬 Watch: Deep dive technical webinar on rebuilding the A6MF1 transmission.
   Est. part cost: $60-$120 for fluid
4. Faulty Transmission Control Module (TCM) ⚪ Low Probability → Shop Transmission Assembly
   How to confirm: This should only be considered after the solenoid, internal harness, and external wiring have all been tested and confirmed to be good. A diagnostic scan tool may show other TCM-related codes. A technician can measure the resistance of the solenoid circuit from the TCM connector pins; if the reading is good there, but the code persists, the TCM driver may be at fault.
   Typical fix: Replace and reprogram the Transmission Control Module. In a documented case for a Kia Soul, a new TCM resolved the P0748 code after all other components tested good.
   Est. part cost: $300-$800

Diagnosis Steps

1. Check the transmission fluid level and condition. This requires a specific procedure on these 'sealed' transmissions. If low, top it off. If dark or burnt-smelling, a fluid change is needed, but be aware this may not fix the underlying issue.
2. Scan the system for any other transmission-related codes. Multiple solenoid codes often point to a wiring harness problem.
3. Inspect the main electrical connector on the outside of the transmission for damage, corrosion, or fluid intrusion.
4. If external checks are okay, the next step is internal. Drain the transmission fluid and remove the transmission oil pan.
5. Visually inspect the internal wiring harness for any obvious signs of damage, like cracks or breaks in the ribbon cable.
6. Remove the valve body to access the solenoids, following proper procedure.
🎬 See this walkthrough on removing the valve body and solenoids.
7. Identify Pressure Control Solenoid 'A'. Test the solenoid's resistance with a multimeter. Compare the reading to the manufacturer's specification (typically 5.0-5.6 ohms at 20°C/68°F). An infinite reading means the solenoid is open and bad.
8. Even if resistance is good, test the solenoid by applying 9V or 12V power and listening for a crisp click. A weak or inconsistent click means the solenoid is mechanically sticking.
9. If the solenoid and harness test good, the problem may lie in the external wiring or the TCM itself.

Parts You'll Likely Need

• Automatic Transmission Control Solenoid (VFS) (OEM #46313-3B030) — This is the most common failure part for code P0748, as identified by Kia's own service bulletin. This part number is for the ON/OFF solenoid which is often replaced as part of the repair. It supersedes part number 46313-3B020.
  Trusted brands: Kia/Hyundai (Genuine OEM), Mando
  OEM price range: $80-$140
  Aftermarket price range: $40-$90
• Automatic Transmission Internal Wire Harness (OEM #46307-3B650) — This harness is a frequent point of failure and is often replaced along with the solenoids as a preventative measure. VIN verification is recommended for this part. This part supersedes 46307-3B610 and 46307-3B620.
  Trusted brands: Kia/Hyundai (Genuine OEM)
  OEM price range: $100-$180
  Aftermarket price range: $60-$120
• Automatic Transmission Solenoid Kit (8pcs) (OEM #N/A (Kit)) — Since accessing the solenoids is labor-intensive, it is highly recommended to replace all 8 solenoids at once. Aftermarket kits are widely available for the A6MF1/A6GF1 transmission.
  Trusted brands: Sheng Hai Auto Parts, Generic aftermarket kits on AliExpress/eBay
  OEM price range: N/A
  Aftermarket price range: $90-$200
• Automatic Transmission Fluid (SP-IV) — The fluid must be drained to perform the repair and should be replaced with new, correct-specification fluid. Approximately 5-6 quarts are needed for a drain and fill.

Related Codes That Often Appear With This One

• P0741 — Torque Converter Clutch Circuit Performance or Stuck Off. This can appear with P0748 because the pressure control solenoids directly impact the operation of the torque converter. This code is also listed in TSB TSBTRA051R1.
• P0753, P0758, P0763, etc. — These are electrical fault codes for other shift solenoids (B, C, D, etc.). If multiple solenoid codes appear at once, it strongly points to a failing internal wiring harness or a bad ground/power feed to the solenoids, rather than multiple individual solenoid failures.
• P0700 — Transmission Control System Malfunction. This is a generic code indicating the TCM has stored a fault, which in this case would be P0748. It often appears alongside more specific transmission codes.

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Addresses DTCs P0741, P0743, P0748, and others on 6-speed automatic transaxles, advising replacement of the solenoids instead of the entire transaxle.

Platform-Specific Known Issues

• A Technical Service Bulletin (TSBTRA051R1) exists for this issue, confirming it's a recognized problem by the manufacturer.
• Owner forums for Kia and Hyundai vehicles with the A6MF1/A6GF1 transmission are filled with accounts of this exact P0748 failure, with the solenoid and/or internal harness replacement being the definitive fix.
• In a documented YouTube video, a 2011 Kia Soul with P0748 that had already had the solenoids and harness checked was ultimately fixed by replacing the main computer (TCM/PCM), though this is a less common cause.

Mechanic-Grade Diagnostic Values

• Resistance of Variable Force Solenoids (VFS) — expected: 5.0 to 5.6 Ohms at 20°C (68°F). Some sources state 5.1 or 5.3 Ohms as a precise target.. Failure: An infinite reading (open circuit), zero reading (short circuit), or a value significantly outside the specified range.
• Resistance of On/Off Shift Solenoids (SSA, SSB) — expected: 10 to 11 Ohms.. Failure: A reading significantly outside this range indicates a faulty on/off solenoid. While not directly P0748, testing all solenoids is common practice during the repair.
• Solenoid Functional 'Click' Test — expected: A crisp, audible click when 9V or 12V is briefly applied to the solenoid's terminals.. Failure: No click, a weak click, or an inconsistent click suggests the solenoid is mechanically sticking or has an internal failure, even if the resistance test passes.

Scan Tool Commands That Help

• Kia GDS (Global Diagnostic System) or equivalent advanced scanner: TCM Relearn / Learning Procedure — This procedure is required after replacing the transaxle assembly, the TCM, or updating the TCM software. It allows the module to learn the engagement points and hydraulic characteristics of the new components. Failure to perform this can result in poor shift quality even after the repair.
• Kia GDS (Global Diagnostic System) or equivalent advanced scanner: Actuation Test — To command a specific solenoid ON or OFF while monitoring system data. This can help verify if the TCM is capable of sending the signal and if the circuit responds, helping to isolate a faulty driver in the TCM.

Wiring & Ground Locations

• TCM/PCM Main Connector — The Transmission Control Module (TCM) is located in the engine compartment. The specific location can vary slightly by model year and engine.. This is where a technician can test the resistance and continuity of the entire solenoid circuit (external wiring, internal harness, and solenoid coil) from a single point without opening the transmission. This helps determine if the fault is internal or external to the transmission case.
• Main Transmission Case Connector — On the exterior of the transmission case, where the main vehicle harness connects to the transmission's internal components.. This connector is a common point for corrosion, fluid intrusion, or physical damage. A poor connection here can cause P0748 and other electrical codes. Testing at this connector can isolate the problem between the internal harness/solenoid and the external wiring going to the TCM.

Real Owner Repair Stories

• 2CarPros Forum User (2004 Kia Sorento (with similar transmission control principles)) — Slipping in first gear, P0748 code present after installing a used transmission.
  ❌ Tried (didn't work) Installing a used transmission, flushing lines, and replacing the filter did not resolve the issue initially.
  ✅ What actually fixed it The user swapped the solenoids from the old, original transmission into the replacement (used) transmission. This made the P0748 code disappear, indicating the issue was with the solenoids in the used unit.

OEM Part Supersession History

• 46307-3B610, 46307-3B620 → 46307-3B650 — Updated design for the internal transmission wiring harness to improve durability and prevent cracking of the ribbon cable.
  Heads up: The updated harness may have an integrated transmission fluid temperature sensor, whereas the original design had a separate, disconnectable sensor. It is always recommended to install the latest version of the harness.

Model Year Variations Within This Range

• 2012-2014: While the core A6MF1/A6GF1 transmission is used, there were running changes to the internal wiring harness. Early models may have the original harness (e.g., 46307-3B610), while later models may have come from the factory with an updated version. Regardless of the original part, the latest superseded part number (46307-3B650) should be used for replacement to ensure reliability.