P0748 on 2011-2015 Kia Sorento: Pressure Control Solenoid 'A' Electrical Fault Guide

What's Unique About the 2011-2015 Kia SORENTO

For the second-generation Kia Sorento (equipped with the A6MF1/A6MF2 transmission), this code is frequently linked to manufacturer-issued Technical Service Bulletins (TSBs). Owner complaints and dealer records show that a simple software update for the Transmission Control Module (TSB TRA038) can often resolve the fault. This suggests the original factory software may be too sensitive or have logic errors that incorrectly flag an electrical issue. Before assuming a hardware failure, checking for and performing this software update is a critical, vehicle-specific first step that can save significant time and money.

Diagnostic Flowchart

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

Symptoms You May Notice

• Harsh, abrupt, or delayed gear shifts.
• Vehicle enters 'limp mode', often stuck in 2nd or 3rd gear.
• Engine sputtering or stalling, especially when coming to a stop.
• Check Engine Light is illuminated.
• Decreased fuel economy due to inefficient shifting or inability to use overdrive.
• Transmission slipping between gears.
• A noticeable 'bang' or 'thump' when shifting into Drive or Reverse.

Most Likely Causes

1. Outdated Transmission Control Module (TCM) Software 🔴 High Probability → Shop Transmission Assembly Multiple owner complaints, like NHTSA ODI #10863738, confirm that dealers performed a TCM reprogram per TSB TRA038 to fix this exact code, indicating the original software logic is a known issue. This is often the first step a dealership will take.
   How to confirm: A Kia dealership or a qualified independent shop with access to Kia's diagnostic system (KDS) can check if the TSB TRA038 update is applicable to your vehicle's VIN and if it has been performed.
   Typical fix: Reprogramming the TCM with the updated software. This can cost between $100-$250 at a dealer.
   Est. part cost: $0
2. Faulty Pressure Control Solenoid 'A' or Internal Harness 🔴 High Probability → Shop Transmission Valve Body Kia issued TSB TSBTRA051R1 specifically instructing technicians to replace shift solenoids for this code, rather than the entire transaxle, confirming it's a common failure point. The internal wiring harness that connects the solenoids to the main connector is also a frequent point of failure due to constant heat and fluid exposure.
   How to confirm: After confirming the TCM software is up to date, a technician can test the solenoid's internal resistance with a multimeter. 🎬 Watch: How to test and clean your transmission solenoids. A reading outside the typical 5.0-5.6 ohm range indicates failure. This requires accessing the valve body inside the transmission pan. The internal harness should also be visually inspected for brittle or broken wires.
   Typical fix: Replace the Pressure Control Solenoid 'A'. Kia/Hyundai often do not sell individual solenoids and require replacement of the entire solenoid/harness assembly. 🎬 See this walkthrough on removing and replacing shift solenoids.
   Est. part cost: $60-$250
3. Damaged Wiring or Corroded Connectors 🟡 Medium Probability The main external wiring harness to the transmission is exposed to heat, vibration, and road debris, which can cause wires to fray or the main connector pins to become contaminated or corroded over time.
   How to confirm: Visually inspect the wiring harness leading to the transmission for any signs of damage, chafing, or corrosion at the main connector. A technician can perform a continuity test on the specific wires for the solenoid 'A' circuit from the TCM to the transmission.
   Typical fix: Repair the damaged section of the wire or clean/replace the corroded connector.
   Est. part cost: $10-$50
4. Low or Dirty Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly While not specific to this vehicle, low fluid can cause pressure issues and dirty/contaminated fluid can clog solenoid passages or cause them to stick, leading to electrical faults from the solenoid working overtime.
   How to confirm: Check the transmission fluid level and condition. The fluid should be at the correct level and bright red (Kia SP-IV), not dark brown or smelling burnt.
   Typical fix: Perform a transmission fluid drain-and-fill or a full fluid exchange. Replace the transmission filter at the same time. This is required if the pan is dropped for solenoid service.
   Est. part cost: $70-$200

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly While rare, the module that controls the solenoid can fail internally, specifically the driver circuit for that solenoid. This should only be considered after all other possibilities (software, solenoid, wiring) have been exhaustively ruled out.

Diagnosis Steps

1. Check the transmission fluid level and condition. Address any low or dirty fluid first, as this can cause a variety of issues.
2. Scan the TCM for any other related trouble codes to get a full picture of the fault.
3. Crucial Step: Contact a Kia dealer or qualified shop to determine if TSB TRA038 (TCM software update) is applicable to your vehicle's VIN and if it has been performed. If not, this is the most logical and cost-effective next step.
4. If the code persists after the software update, visually inspect the transmission's main external electrical connector and wiring harness for visible damage, corrosion, or loose connections.
5. If the external wiring is okay, the transmission pan must be removed to access the valve body and solenoids.
6. Perform a resistance test on the Pressure Control Solenoid 'A'. A typical reading for this transmission's solenoids is around 5.0-5.6 ohms. An open circuit (infinite resistance) or short circuit (zero resistance) confirms a failed solenoid.
7. While the pan is off, carefully inspect the internal wiring harness that connects all the solenoids. Look for brittle plastic, broken wires, or damaged connectors, as this harness is a common failure point.
8. If the solenoid and internal harness test good, check for continuity and voltage on the wiring between the TCM and the transmission's main connector to rule out an external harness issue.
9. If all wiring and solenoids are confirmed to be good, the final step is to diagnose the Transmission Control Module (TCM) itself, which is a rare but possible failure.
🎬 Watch: Diagnosing electrical faults and repairing the control module.

Parts You'll Likely Need

• Transmission Solenoid Assembly/Harness (OEM #46313-3B030, 46313-3B073 (Verify with VIN)) — This is the most common hardware failure. The solenoid itself fails or the integrated internal harness breaks. Kia/Hyundai often service this as a complete assembly rather than individual solenoids.
  Trusted brands: Genuine Kia/Hyundai, Rostra, Dorman
  OEM price range: $150-$250
  Aftermarket price range: $80-$150
• Automatic Transmission Fluid (OEM #Kia Genuine ATF SP-IV) — Fluid must be drained to access the solenoids and should be replaced with the correct specification fluid. A typical drain and fill requires 4-5 quarts.
  Trusted brands: Kia Genuine ATF SP-IV, Idemitsu TLS-LV (SP-IV equivalent), Valvoline MaxLife Multi-Vehicle Full Synthetic (SP-IV compatible)
  OEM price range: $15-$25 per quart
  Aftermarket price range: $10-$20 per quart
• Transmission Pan Gasket (OEM #45285-3B810 (Verify with VIN)) — A new gasket is required to prevent leaks after removing the transmission pan for service. Some technicians prefer using a high-quality RTV sealant designed for transmissions.
  Trusted brands: Fel-Pro, Mahle, Genuine Kia
  OEM price range: $20-$40
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0700 — This is a generic code indicating the TCM has stored a fault. It will almost always be present alongside a specific transmission code like P0748.
• P0743 — This code relates to the Torque Converter Clutch (TCC) solenoid circuit. Since both are electrical solenoid codes within the same transmission, a shared wiring, power, ground, or TCM issue could trigger both.
• P0753 — This code is for Shift Solenoid 'A' Electrical. TSB TSBTRA051R1 groups P0748 with P0753 and other solenoid codes, indicating they share a common failure pattern and are often addressed with the same repair (solenoid replacement).

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Advises replacing various shift solenoids for a list of DTCs including P0748, and explicitly states not to replace the transaxle.
• TRA038: Mentioned in owner complaints as a TCM software reprogram performed by dealers to resolve the P0748 code and related harsh shifting complaints.

Platform-Specific Known Issues

• A known issue requiring a TCM software update (TSB TRA038) can cause this code to appear, as reported by owners in NHTSA complaints.
• Kia issued TSB TSBTRA051R1 to address multiple solenoid-related DTCs, including P0748, by replacing the solenoids instead of the entire transaxle, confirming this is a known component-level weakness.
• Owners on forums like 2carpros.com have confirmed that swapping solenoids from a known-good transmission can resolve the P0748 code, pointing directly to the solenoid as the culprit.

Mechanic-Grade Diagnostic Values

• Pressure Control Solenoid Coil Resistance — expected: 5.0 to 5.6 Ω at 20°C (68°F). Some sources state a value of 5.1 Ω.. Failure: A reading of infinite resistance (open circuit) or near-zero resistance (short circuit).
• Transmission Fluid Temperature Sensor Resistance — expected: Approximately 2.5k Ohms (2500 Ohms) at 68°F (20°C).. Failure: A significantly different reading, or an open/short circuit, which can cause the TCM to command incorrect line pressures.
• Solenoid Supply Voltage from TCM — expected: 12 V ± 1 V when the TCM commands the solenoid to actuate.. Failure: Absence of voltage when commanded ON points to a wiring or TCM driver issue.

Scan Tool Commands That Help

• Kia GDS (Global Diagnostic System) / KDS (Kia Diagnostic System): Actuation Test — After checking wiring, a technician can use the OEM scan tool to manually command the Pressure Control Solenoid 'A' on and off. This verifies if the solenoid clicks and if the TCM driver circuit is capable of sending the signal, helping to isolate the fault between the TCM, wiring, and solenoid.
• Kia GDS (Global Diagnostic System) / KDS (Kia Diagnostic System): Vehicle S/W Management — This function is used to perform the TCM software update as specified in TSB TRA038. It is also used for any necessary programming or learning procedures after replacing the TCM or, in some newer transmissions, the solenoids themselves.

Wiring & Ground Locations

• Transmission Main Connector (External) — On the outside case of the A6MF1/A6MF2 transmission.. This is the primary point for testing the solenoid and sensor circuits without removing the transmission pan. Technicians can perform resistance and voltage checks from this connector to the TCM.
• Solenoid 'A' Circuit Pins — Within the transmission main connector. P0748 often corresponds to Shift Solenoid SL1, which uses Pins 5 (SL1+) and 10 (SL1-). Note: Pinouts can vary, always confirm with a vehicle-specific diagram.. Knowing the specific pins allows for precise testing of the solenoid's resistance and checking for shorts or opens in the wiring harness between the TCM and the transmission.
• Transmission Ground — A grounding strap or bolt connecting the transmission case to the vehicle's chassis/frame.. A poor ground connection for the transmission can cause a variety of electrical issues, including erratic sensor readings and incorrect solenoid operation, potentially triggering a P0748 code.

Real Owner Repair Stories

• 2CarPros Forum User 'BCMULLEN95' (Kia Sorento (year not specified, but in the relevant generation)) — After swapping in a used transmission, the car was slipping in first gear and throwing code P0748.
  ❌ Tried (didn't work) Replacing the transmission with a used unit, replacing the filter, and flushing the lines did not solve the P0748. The user also tested the solenoids on the replacement transmission and reported their resistance values were within spec.
  ✅ What actually fixed it The user swapped the solenoids from the original (old) transmission into the replacement (used) transmission. This action made the P0748 code disappear, indicating the solenoid in the replacement unit was faulty despite testing within resistance specifications.

OEM Part Supersession History

• 46313-3B020 → 46313-3B030 — Standard part revision and improvement by the manufacturer.
  Heads up: The new part number (46313-3B030) is the correct service replacement for the original.

Model Year Variations Within This Range

• 2011-2015: The Sorento used different versions of the 6-speed transmission based on the engine. Models with the 2.4L I4 engine typically have the A6MF1 transmission, while models with the 3.3L or 3.5L V6 have the A6MF2. While the P0748 fault is common to both, and the solenoids are often the same, sourcing a complete used transmission requires an exact match as bracket mounting points and internal ratios can differ.