P0773 on 2011-2014 Kia Forte Koup: Shift Solenoid 'E' Electrical Fault Guide

What's Unique About the 2011-2014 Kia FORTE KOUP

The 6-speed automatic transmission (model A6GF1 for 1.6L and the similar A6MF1 for 1.8L/2.0L engines) used in this era of Kia Forte is known for shift solenoid failures. Kia acknowledged this pattern by issuing Technical Service Bulletin #TSBTRA051R1, which covers P0773 and other related codes. The bulletin specifically advises technicians to replace the faulty solenoids instead of the entire transaxle, confirming this is a recognized component-level weakness. Due to heat and fluid exposure, the entire internal wire harness assembly which houses the solenoids often fails as a unit.

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 end of the first generation Forte Koup (TD, 2011-2013) 🎬 Watch: Top 5 common problems for the 1st Gen Forte Koup and the start of the second generation (YD, 2014). Both generations used a 6-speed automatic transmission (A6GF1/A6MF1) where this fault is known to occur, and the TSB #TSBTRA051R1 is applicable to these models.

Symptoms You May Notice

• Harsh, jerky, or delayed shifts
• Transmission getting stuck in one gear (often 3rd gear limp mode)
• Illuminated Check Engine Light
• Transmission slipping (engine RPMs increase but speed does not)
• Decreased fuel economy
• Inability to shift into certain gears
• Vehicle may stall when shifting into Drive or Reverse

Most Likely Causes

1. Failed Shift Solenoid 'E' / Internal Harness Assembly 🔴 High Probability → Shop Transmission Valve Body This is a well-documented failure point on the A6GF1/A6MF1 6-speed automatic transmission, as acknowledged by Kia's TSB #TSBTRA051R1. The internal wiring and solenoid coils are susceptible to failure from heat and age.
   How to confirm: A mechanic can test the solenoid's electrical resistance with a multimeter after removing the transmission pan. For the on/off solenoids like 'E' (SS-A), the resistance should be between 10-11 Ohms. A reading outside this range (like infinity for an open circuit) confirms failure. A high-end scan tool like the Kia GDS can also attempt to actuate the solenoid and listen for a click. 🎬 See how to diagnose and test solenoids on most Kia models
   Typical fix: Replace the faulty solenoid. However, the most common and recommended repair is to replace the entire internal transmission wire harness (OEM Part #46307-3B650), which includes all the solenoids, as a preventative measure.
   Est. part cost: $140-$250 for the full harness assembly
2. Low or Contaminated Transmission Fluid 🟡 Medium Probability → Shop Transmission Assembly The A6GF1/A6MF1 transmission is sensitive to fluid level and condition. Old, burnt, or contaminated fluid can cause solenoids to stick or fail electronically, though an 'electrical' code points more directly to the component itself.
   How to confirm: Check the transmission fluid level and condition. The correct fluid is SP-IV ATF, which should be bright red and not smell burnt. This transmission does not have a dipstick, so the level must be checked via a plug on the side of the case with the fluid at a specific temperature (122-140°F / 50-60°C).
   Typical fix: Perform a transmission fluid drain-and-fill. If the fluid is very dirty, a full flush may be recommended. This is often done in conjunction with the solenoid replacement.
   Est. part cost: $50-$150
3. Damaged Wiring or Connectors ⚪ Low Probability
   How to confirm: Visually inspect the external transmission wiring harness for damage. The internal harness, which connects to the solenoid, is the more likely culprit and is inspected after removing the transmission pan.
   Typical fix: Repair or replace the damaged section of the wiring harness. If the internal harness is brittle or damaged, it is replaced as a unit (see first cause).
   Est. part cost: $20-$200

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly This is very rare. The TCM should only be suspected after the solenoid harness and external wiring have been thoroughly tested and confirmed to be good. A failure here often involves a bad driver IC on the circuit board, which requires specialized electronic repair.

Diagnosis Steps

1. Scan the vehicle's computer for P0773 and any other stored codes.
2. Check the automatic transmission fluid (ATF) level and condition. This must be done at operating temperature (122-140°F / 50-60°C) via the check plug. Ensure it is the correct Kia/Hyundai SP-IV fluid.
3. Inspect the external transmission wiring harness and connectors for any visible damage, corrosion, or loose connections.
4. If the fluid and external wiring are good, drain the transmission fluid and remove the transmission oil pan to access the valve body and solenoids.
5. Identify Shift Solenoid 'E' (SS-A). In the A6GF1/A6MF1, it is one of the two black, on/off type solenoids.
6. Test the resistance of the suspect solenoid with a multimeter. It should measure between 10-11 Ohms at room temperature. An open or shorted reading indicates failure.
7. Inspect the internal wiring harness for any signs of damage, brittleness, or discoloration on the connectors.
8. If the solenoid tests bad, it is highly recommended to replace the entire internal wire harness assembly (which includes all solenoids) rather than just one.
🎬 Watch this walkthrough on removing and replacing the transmission shift solenoid
9. If the solenoid and wiring test good, the issue may be with the Transmission Control Module (TCM), though this is the least likely cause.

Parts You'll Likely Need

• Automatic Transmission Wire Harness Assembly (OEM #46307-3B650) — This is the most common and recommended fix. It replaces all solenoids and the internal wiring, which is a known failure point confirmed by TSB #TSBTRA051R1.
  Trusted brands: Kia (OEM), Hyundai (OEM)
  OEM price range: $140-$210
  Aftermarket price range: $100-$160
• Automatic Transmission Fluid (ATF) — The transmission must be drained to access the solenoids. It must be refilled with approximately 5-6 quarts of the correct fluid, Kia/Hyundai SP-IV.
  Trusted brands: Kia/Hyundai (OEM), Idemitsu, Valvoline
  OEM price range: $15-$25 per quart
  Aftermarket price range: $10-$18 per quart
• Transmission Oil Pan Gasket — The old gasket should be replaced when the pan is removed to prevent leaks. Some models use RTV sealant instead of a pre-formed gasket.
  Trusted brands: Kia (OEM), Fel-Pro, Mahle
  OEM price range: $20-$40
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• P0741 — Torque Converter Clutch Circuit Performance or Stuck Off
• P0753 — Shift Solenoid 'A' Electrical
• P0758 — Shift Solenoid 'B' Electrical
• P0763 — Shift Solenoid 'C' Electrical
• P0768 — Shift Solenoid 'D' Electrical

Technical Service Bulletins (TSBs) & Recalls

• TSBTRA051R1: Addresses a series of shift solenoid DTCs, including P0773, on 6-speed automatic transaxles. It advises replacing the individual solenoids or harness if codes are present, rather than replacing the entire transmission assembly. It confirms the repair can be done with the transaxle in the vehicle.

Platform-Specific Known Issues

• Kia issued Technical Service Bulletin #TSBTRA051R1 for multiple vehicles using this 6-speed automatic transmission, including the Forte. It acknowledges that codes like P0773 are likely caused by a faulty solenoid and that only the solenoid/harness should be replaced, not the entire transaxle.

Mechanic-Grade Diagnostic Values

• Shift Solenoid 'E' (SS-A) Resistance — expected: 10 - 11 Ohms. Failure: A reading of infinity (open circuit) or near zero (short circuit).
• Variable Force Solenoid (VFS) Resistance — expected: 5.1 Ohms. Failure: A reading significantly different from 5.1 Ohms. This is for comparison against the other solenoids in the harness (e.g., TCC, 3-5-R, OD, UD, 2-6).
• Transmission Fluid Temperature for Level Check — expected: 122°F - 140°F (50°C - 60°C). Failure: Checking the fluid level when the fluid is too cold or too hot will result in an inaccurate reading, leading to under- or over-filling.

Scan Tool Commands That Help

• Kia GDS (Global Diagnostic System): Resetting Auto T/A Values / Init Of TCU Learning — This function must be performed after replacing the transmission or the solenoid harness assembly. It erases the old adaptive shift data stored in the TCM, allowing the module to relearn shift points and pressures with the new components for optimal shift quality.
• Kia GDS (Global Diagnostic System): Actuation Test — This bidirectional test allows a technician to command a specific solenoid (like SS-A) to turn on and off. The technician can then listen with a stethoscope for a clicking sound from the solenoid, which helps confirm if the solenoid is mechanically responding to the command.

Wiring & Ground Locations

• Main Transmission Case Connector — On the top or side of the transmission case, where the main vehicle harness plugs into the transmission.. This is the primary external test point for checking the resistance of all internal solenoids without removing the transmission pan. A technician can use a pinout chart to identify the two pins corresponding to Shift Solenoid 'E' (SS-A) and measure its resistance directly at this connector.
• Solenoid Identification by Color — On the valve body, inside the transmission oil pan.. The A6MF1 valve body uses several solenoids that look similar but have different functions and electrical properties. Shift Solenoids 'A' and 'B' (the on/off type) are typically black. The other Variable Force Solenoids (VFS) are different colors like yellow, blue, and red. Correctly identifying the black SS-A solenoid is critical for targeted testing.

OEM Part Supersession History

• 46307-3B610, 46307-3B620 → 46307-3B650 — Component revision and consolidation. The newer part number is the current replacement for a wide range of Hyundai/Kia models with the 6-speed automatic transmission.
  Heads up: The part 46307-3B650 is the correct and backward-compatible replacement for the earlier numbers on this vehicle.

Model Year Variations Within This Range

• 2011-2014: While the Forte Koup transitioned from the first generation (TD) to the second generation (YD) in 2014, both model years within this range utilize the same family of 6-speed automatic transmissions (A6GF1/A6MF1) and suffer from the same known solenoid failure issues. The TSB #TSBTRA051R1 and the replacement harness part #46307-3B650 apply to the entire 2011-2014 range.