P0743 on 2011-2014 Kia Sedona: Torque Converter Clutch Solenoid Fault Guide

What's Unique About the 2011-2014 Kia SEDONA

The 2011-2014 Kia Sedona uses a 6-speed automatic transaxle (A6MF2) that is known to have issues with its various solenoids. Kia acknowledged this by issuing Technical Service Bulletin #TSBTRA051R1, which specifically lists P0743 as a code that should be addressed by replacing the solenoid itself, rather than performing a more costly transmission or torque converter replacement. This makes the diagnosis more straightforward than on other vehicles where the cause might be less certain. This issue is common across many Hyundai and Kia models using this same transmission family. A high-failure item on these transmissions is the internal wiring harness, which can become brittle and cause solenoid circuit codes.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light is on
• Transmission will not lock the torque converter at highway speeds
• Higher than normal engine RPMs when cruising
• Decreased fuel economy
• Transmission may shift harshly or feel like it's slipping
• In some cases, the transmission may enter a 'limp mode', stuck in a single gear
• Engine may stall when coming to a stop

Most Likely Causes

1. Failed Torque Converter Clutch (TCC) Solenoid 🔴 High Probability → Shop Automatic Transmission Torque Converter This is a known issue for this platform, as documented by Kia in TSB #TSBTRA051R1, which advises replacing the solenoids for this code. The transmission family (A6MF1/2) is widely known for solenoid failures.
   How to confirm: A technician can test the solenoid's resistance with a multimeter (it should be around 5.1 ± 0.3 Ω) or command it on/off with a professional scan tool to check its response. A simple bench test can be done with a 9-volt or 12-volt power source to listen for an audible 'click'.
   Typical fix: Replace the TCC solenoid (OEM Part #46313-3B770), which is located inside the transmission on the valve body, accessible after removing the side cover. 🎬 Watch: Step-by-step guide to removing and replacing transmission solenoids.
   Est. part cost: $60-$150
2. Wiring or Connector Issue 🟡 Medium Probability Corrosion can build up inside the main transmission wiring harness connector where it attaches to the transmission case, causing an open or short circuit. This is a known issue on platform mates like the Sorento. The internal transmission harness is also 🎬 See how a corroded harness connector causes these specific codes. considered a high-failure component prone to issues near the case connector.
   How to confirm: Visually inspect the main transmission wiring harness connector for any signs of green or white corrosion, moisture intrusion, or damaged pins. A technician found this exact issue on a 2014 Sorento with P0743, confirming the solenoids were good but the connector pins were corroded. Test for continuity and proper voltage at the solenoid connector.
   Typical fix: Clean the connector terminals thoroughly. If corrosion is severe, the external wiring harness pigtail and/or the internal transmission harness (Part # 46307-3B650) may need to be replaced.
   Est. part cost: $20-$250
3. Low or Dirty Transmission Fluid 🟡 Medium Probability → Shop Transmission Assembly Many owners are unaware that this 'sealed' transmission requires fluid changes. Old, contaminated, or low fluid can cause solenoids to stick, overheat, or function improperly.
   How to confirm: Check the transmission fluid level and condition. If the fluid is dark, burnt-smelling, or contains debris, it can clog solenoid passages and cause electrical faults.
   Typical fix: Perform a transmission fluid and filter change using Kia-specific SP-IV fluid. If the fluid is heavily contaminated, it may indicate a more severe internal problem.
   Est. part cost: $50-$150
4. Faulty Powertrain Control Module (PCM) ⚪ Low Probability → Shop Engine Control Module (ECM)
   How to confirm: This should be the last resort after all other possibilities (solenoid, fluid, wiring) have been thoroughly ruled out by a professional.
   Typical fix: Replace and reprogram the PCM.
   Est. part cost: $500-$1000

Diagnosis Steps

1. Check the transmission fluid level and condition. Top off or change if necessary.
2. Connect a professional OBD-II scanner to read the codes and view live transmission data, such as TCC solenoid command status and slip RPM. The code may set when the PCM detects a difference greater than 200 RPM between the torque converter and the transmission input shaft when lock-up is commanded.
3. Thoroughly inspect the external transmission wiring harness and the main round connector for any obvious damage, corrosion, or loose connections. Disconnect it and check for bent or corroded pins.
4. Following the service manual, drain the transmission fluid and remove the side valve body cover.
5. Disconnect the solenoid connector and measure the resistance of the TCC solenoid. For the A6MF family of transmissions, the linear solenoids (including the TCC) should be approximately 5.1 Ω.
6. If the resistance is out of specification, the solenoid is faulty and must be replaced.
7. If the resistance is correct, the fault likely lies in the wiring. Check the internal and external wiring harnesses between the PCM and the transmission for shorts or open circuits. Pay close attention to the main connector pins and the internal harness, which is a known failure point.
8. If the solenoid and wiring are confirmed to be good, the issue may lie with the Powertrain Control Module (PCM), though this is rare.

Parts You'll Likely Need

• Automatic Transmission Control Solenoid (TCC Solenoid) (OEM #46313-3B770) — This is the most common failure point for code P0743 on this vehicle, as confirmed by a manufacturer TSB. This part is specifically described as the '2-6 Brake and Torque Converter Clutch' solenoid.
  Trusted brands: Kia/Hyundai (OEM), Standard Motor Products
  OEM price range: $95-$150
  Aftermarket price range: $60-$100
• Transmission Valve Body Cover Gasket (OEM #45283-3B810) — This must be replaced anytime the valve body cover is removed to access the solenoids, as it is a one-time use part to prevent leaks.
  Trusted brands: Kia (OEM), Fel-Pro
  OEM price range: $20-$40
  Aftermarket price range: $15-$30
• Automatic Transmission Fluid (OEM #SP-IV) — The transmission fluid must be drained to perform the repair and should be refilled with fluid that meets Kia's SP-IV specification. A drain and fill for this job typically requires 4-5 quarts.
  Trusted brands: Kia/Hyundai (OEM SP-IV), Valvoline MaxLife ATF, Castrol Transmax Full Synthetic Multi-Vehicle
  OEM price range: $15-$25 per quart
  Aftermarket price range: $10-$20 per quart

Related Codes That Often Appear With This One

• P0741 — P0741 indicates 'TCC Circuit Performance or Stuck Off', which is a related mechanical/performance issue with the same system. TSB TSBTRA051R1 also covers this code. An electrical failure (P0743) often directly causes the performance problem (P0741).
• P0740 — P0740 is a more general 'TCC Circuit Malfunction' code that can appear alongside the more specific P0743.
• P0748, P0753, P0758, etc. — These are all electrical fault codes for other transmission solenoids. As noted in TSB TSBTRA051R1, it's common for multiple solenoids to be flagged, indicating a potential systemic issue with the solenoid pack, internal harness, or main connector.
• P2709 — This is a code for 'Shift Solenoid F Electrical'. A technician documented finding P0743 and P2709 together on a 2014 Sorento, where the cause was a corroded main connector, not faulty solenoids.

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Provides information on replacing various shift solenoids for multiple DTCs including P0743, advising against transaxle replacement. It covers the A6MF1/2 family of 6-speed transmissions.

Platform-Specific Known Issues

• A Technical Service Bulletin (TSBTRA051R1) was issued by Kia for 6-speed automatic transaxles, noting that code P0743 (among others) is often caused by a faulty solenoid and that the solenoid should be replaced, not the entire transaxle.
• Real-world mechanic reports on platform mates like the Sorento show that corrosion in the main transmission harness connector can cause P0743 and other solenoid codes, even when the solenoids themselves test good. This should be a primary inspection point before ordering parts.
• The internal wiring harness on the A6MF transmission family is a known high-failure component that can become brittle and cause intermittent open or short circuits for the solenoids.

Mechanic-Grade Diagnostic Values

• TCC Solenoid (Linear Type) Coil Resistance — expected: 5.1 Ohms. Failure: A reading of infinite resistance (open circuit) or near-zero ohms (short circuit).
• On/Off Type Solenoid Coil Resistance — expected: 10-11 Ohms. Failure: A reading significantly higher or lower than the specification.
• Solenoid Activation 'Click' Test — expected: An audible 'click' should be heard when 9V or 12V is briefly applied to the solenoid's terminals.. Failure: No click indicates the solenoid is mechanically stuck or electrically failed.

Scan Tool Commands That Help

• Kia GDS (or advanced aftermarket scanner): TCC Solenoid Activation Test / Actuation Test — Use this bidirectional command to manually energize the TCC solenoid while the vehicle is stationary. A technician can listen for a click and monitor circuit voltage to confirm if the solenoid is responding to TCM commands. This helps isolate a faulty solenoid from a wiring or TCM driver issue.
• Kia GDS (or advanced aftermarket scanner): Resetting Auto Trans Adaptive Values — This function must be performed after replacing transmission components like solenoids or the entire valve body. It clears the learned shift adaptations, allowing the TCM to relearn with the new parts.

Wiring & Ground Locations

• Internal Valve Body Wiring Harness — Inside the transmission, connected to the valve body solenoids and routing to the main case connector.. This harness is a known high-failure component. It can become brittle from heat and fluid exposure, leading to intermittent open or short circuits that trigger solenoid codes like P0743.
• Transmission Ground Strap — Typically a braided strap connecting the transmission case to the vehicle's chassis or engine block.. A poor or corroded ground connection can cause a variety of electrical issues, including erratic solenoid operation and incorrect sensor readings, potentially contributing to a P0743 code. A general list of grounding points for Kia vehicles includes the transmission case.

Real Owner Repair Stories

• YouTube channel 'Transmission Repair' (Hyundai/Kia with A6MF1 transmission (same family as Sedona's A6MF2)) — Harsh engagement, slipping, no codes present but symptoms are consistent with solenoid/valve body issues.
  ❌ Tried (didn't work) Not specified, video focuses on direct diagnosis.
  ✅ What actually fixed it The video demonstrates testing the solenoids for resistance (5 ohms for PWM, 10 ohms for on/off) and performing a click test. The final fix demonstrated is cleaning the solenoids with brake cleaner while actuating them with a power source, or replacing them if they fail the tests. This confirms the common failure and fix for this transmission family.

OEM Part Supersession History

• 46307-3B610 / 46307-3B620 → 46307-3B650 — Updated internal transmission wiring harness. The original harness had a separate temperature sensor, while the updated version has the sensor integrated into the harness.
  Heads up: It is recommended to always update to the newer harness design when the valve body is removed.

Model Year Variations Within This Range

• 2010-2014: The 2011-2014 Kia Sedona uses the A6MF2 variant of the 6-speed automatic transmission. While functionally very similar to the A6MF1 found in many other Kia/Hyundai models, there can be minor differences in internal components or case design. However, the solenoids, TSB, and common failure patterns for P0743 are consistent across this family.