P0773 on 2011-2015 Kia Optima: Shift Solenoid 'E' Fault Causes and Fixes

What's Unique About the 2011-2015 Kia OPTIMA

The 6-speed automatic transmission (A6MF series) in this generation of Kia Optima is generally considered reliable, often outlasting the vehicle's engine. However, failures of the internal shift solenoids are a known weak point. The issue was common enough that Kia released a Technical Service Bulletin (TSB #TSBTRA051R1) specifically covering code P0773, among others. The bulletin explicitly advises replacing the individual solenoids, which is a much less expensive repair than replacing the entire transmission valve body or the whole transmission unit. The 2011-2015 Optima typically uses the A6MF1 or A6MF2 variant of this transmission.

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
• Harsh, jerky, or delayed shifts
• Transmission slipping between gears
• Vehicle stuck in one gear (limp mode)
• Failure to shift into or out of a gear
• Decreased fuel economy
• Transmission overheating
• Transmission warning lamp illuminated on the dash
• Engine stalls when shifting into Drive or Reverse

Most Likely Causes

1. Failed Shift Solenoid 'E' 🔴 High Probability This is a known issue acknowledged by Kia in TSB #TSBTRA051R1, which specifically lists P0773 and recommends solenoid replacement. The solenoids are a common failure point in this 6-speed automatic transmission. The entire solenoid pack, which includes multiple solenoids of different colors (black, red, yellow, blue), is often replaced as a unit.
   How to confirm: A mechanic can use a scan tool to actuate the solenoid and listen for a click. They can also test the solenoid's electrical resistance with a multimeter after removing the transmission pan. 🎬 See how to test the solenoid using a multimeter. The resistance for the on/off solenoids (like SSA/SSB, which may be designated 'E' in generic OBD-II) should be around 10–11 ohms, while variable force solenoids are around 5.1 ohms.
   Typical fix: Replace the shift solenoid pack. The solenoids are typically replaced as a complete set. A video by 'World Mechanics' on YouTube demonstrates the replacement process on a 2013 Optima with the A6MF1 transmission.
   Est. part cost: $100-$300
2. Low or Contaminated Transmission Fluid 🟡 Medium Probability
   How to confirm: Check the transmission fluid level and condition. The fluid should be at the correct level and appear clean and red. Dark, burnt-smelling fluid indicates a problem and can contribute to solenoid failure.
   Typical fix: Perform a transmission fluid drain and fill, or a complete fluid flush if the fluid is very dirty. This is often done in conjunction with solenoid replacement.
   Est. part cost: $50-$150
3. Damaged Internal Wiring Harness ⚪ Low Probability The internal wiring harness that connects the solenoids can become brittle or damaged over time from heat and constant exposure to transmission fluid. It is recommended to replace the harness, especially on earlier models, with the updated version that has an integrated temperature sensor.
   How to confirm: Visually inspect the wiring harness leading to the solenoids for any signs of damage, corrosion, or loose connections after the transmission pan is removed.
   Typical fix: Repair the damaged section of the wiring harness or replace the entire internal harness (Part number may vary, e.g., 46307-3B650).
   Est. part cost: $20-$100

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): While rare, the TCM itself can fail, sending incorrect signals or no signal to the solenoid. This should only be considered after all other possibilities (solenoid, fluid, wiring) have been thoroughly ruled out. A Hyundai TSB for the same transmission suggests replacing the PCM (which integrates the TCM) only if the code returns after solenoid replacement.
• Worn Transmission Valve Body: The valve body contains passages that the solenoids control. Bores within the valve body, such as the reducing valve bore, can wear out over time, causing pressure loss and shifting issues even with good solenoids.

Diagnosis Steps

1. Scan for Codes: Use an OBD-II scanner to confirm P0773 is present and check for any other related transmission codes.
2. Check Transmission Fluid: Inspect the transmission fluid level and condition. Low or burnt fluid can cause numerous issues and should be addressed first. Note that many of these vehicles do not have a traditional dipstick.
3. Inspect Wiring: Visually inspect the external transmission wiring harness and connectors for any visible damage, corrosion, or loose pins.
4. Test the Solenoid Circuit: A qualified technician can use a professional scan tool to command the 'E' solenoid on and off to check for an audible click. They can also measure the resistance of the solenoid circuit from the transmission connector to check for an open or short. Resistance should be approximately 10-11 Ohms for on/off solenoids or 5.1 Ohms for variable force solenoids.
5. Internal Inspection: If external checks pass, the transmission oil pan must be removed to access the solenoids and internal wiring harness.
6. Replace Solenoids & Harness: 🎬 Watch this step-by-step guide to removing and replacing the solenoids. If the solenoid is confirmed to be faulty, it is best practice to replace the entire solenoid pack and the internal wiring harness. One of the shift solenoids has the part number 46313-3B030.
7. Test Drive: After the repair, fill the transmission with the correct type and amount of fluid (Kia/Hyundai SP-IV specified ATF) and perform a test drive to ensure normal shifting operation is restored. An adaptive value reset using a scan tool is recommended.

Parts You'll Likely Need

• Automatic Transmission Solenoid Pack (OEM #46313-3B030 (Individual Shift Solenoid A/B)) — This is the most common failure part for code P0773 on this vehicle, as documented by an official Kia TSB. The solenoids are typically sold as a complete assembly of 8.
  Trusted brands: Rostra Precision Controls, Dorman, Standard Motor Products (TCS289)
  OEM price range: $250-$400
  Aftermarket price range: $89-$250
• Automatic Transmission Fluid (ATF) — The transmission fluid must be drained to perform the repair and will need to be replaced with new fluid that meets Kia's SP-IV specification.
  Trusted brands: Kia/Hyundai Genuine SP-IV ATF
  OEM price range: $15-$25 per quart
  Aftermarket price range: $8-$15 per quart
• Transmission Oil Pan Gasket — The gasket should be replaced when the oil pan is removed to prevent leaks.
  OEM price range: $20-$40
  Aftermarket price range: $10-$25
• Internal Wire Harness (OEM #46307-3B650 (example, verify by VIN)) — It is highly recommended to replace the internal harness when replacing the solenoids, as it can become brittle. Later designs integrate the temperature sensor.
  Trusted brands: Genuine Hyundai/Kia
  OEM price range: $30-$60

Related Codes That Often Appear With This One

• P0741, P0743, P0748, P0753, P0758, P0763, P0768 — These are all codes related to other shift solenoids in the same 6-speed automatic transmission. They are listed together in TSB #TSBTRA051R1 and often indicate a failure of the entire solenoid pack or a common electrical issue.

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Provides information for replacing various shift solenoids on 6-speed automatic transaxles for codes including P0773, advising against transaxle replacement.
• A similar Hyundai TSB (12-AT-016-1) also covers P0773 for the same family of transmissions, instructing technicians not to replace the transmission but to replace the related solenoid.

Platform-Specific Known Issues

• A Technical Service Bulletin (TSB #TSBTRA051R1) was issued by Kia for multiple models with the 6-speed automatic transmission, including the 2011-2015 Optima. It addresses a group of solenoid-related DTCs, including P0773, and advises replacing the solenoid pack instead of the entire transaxle.

Mechanic-Grade Diagnostic Values

• Resistance of On/Off Shift Solenoids (e.g., SSA, SSB) — expected: 10–11 Ohms. Failure: A reading significantly higher or lower than the expected range, or an open circuit (infinite resistance).
• Resistance of Variable Force Solenoids (VFS) — expected: 5.1 Ohms. Failure: A reading outside of the specified range, indicating a faulty coil.
• Voltage at TCM ground path to chassis — expected: < 0.1 Ω. Failure: Higher resistance indicates a poor ground, which can cause various electrical faults.

Scan Tool Commands That Help

• Kia GDS (Global Diagnostic System): Resetting Auto T/A Values — This function must be used after replacing the transmission, solenoids, or the PCM/TCM to clear learned shift data. Failure to reset adaptations can result in continued poor shift quality even after the hardware is fixed.
• Kia GDS (Global Diagnostic System): Adaptive Value Relearn Drive Cycle — After resetting the adaptive values, a specific drive cycle is required to 'teach' the TCM the correct solenoid duty and line pressure. This involves accelerating gently from a stop through all 6 gears and decelerating slowly to a stop, repeated 5 times.

Wiring & Ground Locations

• Instrument Panel Fuse Box Ground — There is a primary grounding bolt located to the left of the steering wheel, behind the cover for the interior fuse panel.. The Body Control Module (BCM) and other interior modules that communicate with the TCM are grounded here. A poor ground at this location can cause a variety of communication and electrical issues.
• Engine Compartment Fuse Box / Main Grounds — The main fuse box is in the engine compartment. Key grounds for the powertrain are typically located on the engine block, cylinder head, and the transmission case itself.. The TCM/PCM and the transmission solenoids rely on clean grounds to the chassis and engine block. A corroded or loose ground on the transmission case or engine can directly cause electrical faults in the solenoid circuits.
• TCM/ATM Fuse — In the fuse box located in the engine compartment. The specific fuse is often labeled 'ATM' or may be part of a multi-fuse assembly.. This fuse supplies power to the Transmission Control Module. If this fuse is blown, the TCM cannot operate or communicate with the solenoids, which could trigger electrical fault codes.

Real Owner Repair Stories

• YouTube channel 'How to fix trouble code...' (Unspecified Kia/Hyundai with a similar 6-speed automatic transmission.) — Engine shuts off immediately when shifting into Drive or Reverse.
  ✅ What actually fixed it The mechanic diagnosed a faulty shift solenoid by observing its discolored (brown) appearance after removing the valve body. Replacing the single discolored solenoid resolved the issue of the engine stalling when put into gear.

OEM Part Supersession History

• 46307-3B610, 46307-3B620 → 46307-3B650 — Updated design for the internal transmission wiring harness.
  Heads up: The newer harness (46307-3B650) is the recommended replacement for older versions when servicing the solenoids, as it is more durable.

Model Year Variations Within This Range

• 2011-2015: The 2011-2015 Optima could be equipped with either the A6MF1 or A6MF2 transmission depending on the engine (2.0L or 2.4L) and its torque output. The A6MF1 is for engines with up to 170 lb-ft of torque, while the A6MF2 is for engines up to 210 lb-ft. While internally similar, some hard parts may differ to handle the torque, but the solenoid replacement procedure and TSB apply to both.