P0773 on 2011-2014 Kia Optima Hybrid: Shift Solenoid 'E' Causes and Fixes

What's Unique About the 2011-2014 Kia OPTIMA HYBRID

The 6-speed automatic transaxle (A6MF1H/A6MF2H) used in this generation of Kia Optima Hybrid is known to have issues with its shift solenoids. Kia acknowledged this by issuing Technical Service Bulletin #TSBTRA051R1, which covers P0773 and advises technicians to replace the individual solenoids rather than the entire transaxle. This indicates a higher-than-average failure rate for this specific component, making a faulty solenoid the most probable cause for this code on this vehicle. This issue is also prevalent in its direct platform mate, the Hyundai Sonata Hybrid.

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 warning lamp may be illuminated
• Harsh, jerky, or delayed gear shifts
• Transmission getting stuck in one gear (limp mode), often 3rd or 5th gear
• Transmission slipping, where engine RPMs increase but speed does not
• Decreased fuel economy
• Vehicle may stall when put into gear
• Very sluggish acceleration from a standstill

Most Likely Causes

1. Failed Shift Solenoid 'E' or Internal Harness 🔴 High Probability This is a known failure point on this 6-speed automatic transmission, as acknowledged by Kia's Technical Service Bulletin #TSBTRA051R1, which specifically lists P0773 and recommends solenoid replacement. The internal wiring harness that connects the solenoids can also become brittle and fail.
   How to confirm: After accessing the valve body, a technician can test the solenoid's internal resistance with a multimeter. For the on/off solenoids 🎬 Watch: How to test solenoid resistance with a multimeter. (like SSA, SSB) in the A6MF family, the resistance should be approximately 10-11 Ohms. For the Variable Force Solenoids (VFS), it should be around 5.0-5.1 Ohms. A reading of infinity (open circuit) or zero (short circuit) confirms failure. A solenoid can also be tested by applying a 9V or 12V source to check for an audible click, indicating mechanical function. 🎬 Watch: How to clean and test 6-speed transmission solenoids.
   Typical fix: Replace the faulty shift solenoid or, more commonly, the entire solenoid wire harness assembly which includes all solenoids. This requires removing the front transmission cover and valve body to access the components.
   Est. part cost: $60-$400
2. Low or Contaminated Transmission Fluid 🟡 Medium Probability
   How to confirm: Check the transmission fluid level and condition via the fill plug. The fluid should be at the correct level, pinkish-red, and not smell burnt. Dark, dirty, or burnt-smelling fluid indicates a problem and can contribute to solenoid failure.
   Typical fix: Perform a transmission fluid drain and fill with Kia-specified SP-IV fluid. If the fluid is very contaminated, a full fluid exchange (flush) may be recommended by a professional, though this is often debated.
   Est. part cost: $50-$150 for fluid
3. Damaged Wiring or Connectors ⚪ Low Probability
   How to confirm: Visually inspect the main external wiring harness connector at the transmission for any signs of corrosion, breaks, or loose connections. The internal harness is a more likely culprit and is inspected during solenoid replacement.
   Typical fix: Repair or replace the damaged section of the external wiring harness or the connector. If the internal harness is faulty, it is replaced with the solenoid assembly.
   Est. part cost: $20-$200

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): This is very rare and should only be considered after the solenoid, wiring, and fluid have been confirmed to be in good condition. A faulty TCM can send incorrect signals or fail to detect a valid signal from the solenoid.

Diagnosis Steps

1. Scan the vehicle's computer for trouble codes and record any other codes present.
2. Check the level and condition of the automatic transmission fluid. Top off or change if necessary with SP-IV rated fluid.
3. Inspect the external transmission wiring harness and main connector for any visible damage, corrosion, or loose connections.
4. If fluid and external wiring are okay, the next step is to access the transmission's internal components.
5. Drain the transmission fluid and remove the front transmission case cover (NOT the bottom oil pan).
6. Remove the valve body assembly to gain access to the solenoids and internal wiring harness.
7. Visually inspect the internal wiring harness connected to the solenoids for brittleness or damage.
8. Identify and test the resistance of Shift Solenoid 'E' (and others) using a digital multimeter. Compare the reading to the specification (approx. 10-11 Ohms for on/off solenoids, 5.0-5.1 Ohms for VFS solenoids).
9. If any solenoid's resistance is out of spec, it is faulty. It is highly recommended to replace the entire solenoid harness assembly.
10. If all solenoids test good, the issue may lie in the wiring harness connections or, rarely, the TCM itself.

Parts You'll Likely Need

• Automatic Transmission Solenoid Wire Harness Assembly (OEM #46313-3B030) — This is the most common failure point for code P0773 on this vehicle, as confirmed by a manufacturer TSB. This assembly includes all shift solenoids and the internal harness, which can become brittle. Replacing the entire unit is the most reliable repair.
  Trusted brands: Kia (OEM), Hyundai (OEM), Rostra
  OEM price range: $150-$350
  Aftermarket price range: $80-$200
• Automatic Transmission Fluid (OEM #SP-IV) — The fluid must be drained to access the solenoids and should be replaced with 5-6 quarts of new fluid that meets Kia's SP-IV specification to ensure proper transmission function.
  Trusted brands: Kia/Hyundai (OEM), Idemitsu TLS-LV, Valvoline MaxLife ATF
  OEM price range: $15-$25 per quart
  Aftermarket price range: $8-$15 per quart
• Transmission Front Case Cover Gasket/Sealant — The front cover must be removed and re-sealed to prevent leaks. Depending on the specific design, this may be a pre-formed gasket or require a specific RTV sealant.
  Trusted brands: Kia (OEM), Permatex, Fel-Pro
  OEM price range: $30-$60
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0741 — Relates to the Torque Converter Clutch Solenoid circuit. It is listed in the same TSB (TSBTRA051R1) and points to the common solenoid pack/harness failure.
• P0753 — This is for Shift Solenoid 'A' Electrical. It's common to see multiple solenoid codes together if the internal wiring harness is failing or if multiple solenoids in the block have failed due to age or contamination.
• P0763 — This is for Shift Solenoid 'C' Electrical. Like other solenoid codes, it points to a common failure point within the same transmission component group and is also listed in TSB TSBTRA051R1.

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Addresses multiple diagnostic trouble codes (including P0773) related to shift solenoids on 6-speed automatic transaxles. Crucially, it instructs technicians to 'REPLACE THE SOLENOIDS IF CURRENT OR HISTORY CODES ARE PRESENT; DO NOT REPLACE THE TRANSAXLE.'

Platform-Specific Known Issues

• Kia issued Technical Service Bulletin #TSBTRA051R1 for various 6-speed automatic transaxles, including the one in the Optima Hybrid. It acknowledges that codes like P0773 are likely due to solenoid failure and instructs technicians to replace the solenoids, not the entire transaxle.
• Owner Experience: A common story on forums like kia-forums.com involves the car suddenly going into limp-home mode (stuck in gear) with a P0773 code. The owner is often quoted a high price for a transmission replacement at one shop, but a second opinion at a dealer or knowledgeable independent shop correctly identifies the solenoid issue per the TSB, leading to a much cheaper repair by replacing the solenoid block.

Mechanic-Grade Diagnostic Values

• Resistance of On/Off Shift Solenoids (e.g., SSA, SSB) — expected: 10 - 11 Ohms. Failure: A reading of infinity (open circuit), zero (short circuit), or a value significantly outside the expected range.
• Resistance of Variable Force Solenoids (VFS/Linear Solenoids) — expected: 5.0 - 5.1 Ohms. Failure: A reading of infinity (open circuit), zero (short circuit), or a value significantly outside the expected range.
• Solenoid Mechanical Function Test — expected: Audible 'click' when power is applied.. Failure: No click, or a weak/inconsistent click, suggests the solenoid is mechanically stuck even if resistance is correct.
• TCM Ground Path Resistance — expected: < 0.1 Ω. Failure: Resistance higher than 0.1 Ω indicates a poor ground, which can cause various electrical faults.

Scan Tool Commands That Help

• Kia GDS (Global Diagnostic System): DTC Analysis & Actuation Test — The OEM scan tool can perform actuation tests to command a specific solenoid to turn on or off, helping to isolate whether the fault is with the solenoid, wiring, or the TCM's driver circuit. It also provides detailed diagnostic procedures for each specific fault code.
• Kia GDS (Global Diagnostic System): Data Analysis (Live Data) — To monitor the voltage and current commands being sent from the TCM to Shift Solenoid 'E' in real-time while driving or cycling through gears. This can help differentiate between a command problem and a component failure.

Wiring & Ground Locations

• Transmission Ground — A primary grounding point for the transmission and engine is often located on the chassis near the transmission mount or on the engine block itself.. A poor transmission ground can cause erratic behavior and incorrect voltage readings for all transmission sensors and solenoids, potentially triggering electrical fault codes like P0773.
• Interior Fuse Panel Ground — There is a common grounding bolt located to the right of the interior fuse panel (driver's or passenger's side kick panel area) where multiple grounds connect.. The TCM may receive its ground reference from an interior ground point. Verifying this ground is secure is a crucial step in diagnosing any control module-related electrical issue.
• 12V Battery Location (Hybrid) — In the 2011-2014 Optima Hybrid, the 12V auxiliary battery is located in the trunk on the right side, under the floor cover.. All low-voltage electrical systems, including the TCM and solenoids, are powered by the 12V system. When diagnosing, it's important to know the battery location for testing and safety disconnect procedures.

Real Owner Repair Stories

• YouTube video by 'Motorcar Nut' (2015 Kia Optima (with A6MF1 transmission, similar to the Optima Hybrid's A6MF2H)) — General shifting quality problems, which often trigger solenoid codes.
  ❌ Tried (didn't work) The video focuses on the correct diagnostic procedure rather than failed attempts.
  ✅ What actually fixed it The video demonstrates the process of removing the valve body, testing solenoid resistance with a multimeter (showing a reading of ~5 ohms on a VFS), and testing mechanical function by applying 12V to listen for a click. The final fix is cleaning or replacing the faulty solenoid or the entire solenoid assembly.

OEM Part Supersession History

• 46313-3B020 → 46313-3B030 — Part revision or improvement by the manufacturer.
  Heads up: The newer part 46313-3B030 is the correct replacement for the older 46313-3B020 and should be used for repairs.

Model Year Variations Within This Range

• Early vs. Late Models: Early versions of the A6MF transmission family had a transmission fluid temperature sensor that was a separate, disconnectable part from the main internal wire harness. Later/updated harnesses integrate the temperature sensor directly into the harness. When replacing the harness, it is recommended to always use the updated style where the sensor is integrated.