P0712 on 2020-2024 Hyundai Palisade: Transmission Temperature Sensor Causes and Fixes

What's Unique About the 2020-2024 Hyundai Palisade

For the 2020-2024 Hyundai Palisade and its platform-mate the Kia Telluride, this code is specifically addressed by a manufacturer's Technical Service Bulletin (TSB 19-AT-019H). This bulletin acknowledges a known issue with the integrated temperature sensor and directs technicians to replace the entire internal transmission wiring harness. Unlike some vehicles where the TFT sensor is an easily accessible external part, on the Palisade's A8LF1 8-speed automatic, the sensor is located inside the transmission oil pan and requires significant labor to replace.

Symptoms You May Notice

• Check Engine Light is on
• Harsh, delayed, or erratic shifting
• Transmission gets stuck in one gear (limp or 'fail-safe' mode)
• Transmission temperature warning light may be illuminated
• Malfunctioning or disabled torque converter clutch operation
• A 'thump' or 'bang' when shifting from Park to Drive or Reverse

Most Likely Causes

1. Failed Internal Transmission Wiring Harness (with integrated TFT Sensor) 🔴 High Probability → Shop Transmission Assembly This is a very common failure and a known issue acknowledged by Hyundai in TSB 19-AT-019H for the Palisade, Telluride, Santa Fe, and Sonata. The sensor, which is a thermistor, fails internally causing a short circuit, and it is integrated into the harness, which must be replaced as a single unit.
   How to confirm: A professional scan tool will show a fixed, extremely low transmission fluid temperature reading (e.g., -40°F or -40°C). This reading will not change as the vehicle warms up. The TSB provides a diagnostic procedure to confirm the fault lies with the internal harness after ruling out external wiring issues.
   Typical fix: Replace the internal transmission wiring harness (also called the valve body harness). This involves draining the fluid, removing the oil pan, and removing the valve body to access the part.
   Est. part cost: $150-$250

Rare But Worth Checking

• External Wiring or Connector Issue: A short to ground in the wiring between the transmission's main connector and the TCM could also cause this code. This should be ruled out before performing major transmission work, as outlined in the TSB diagnostic steps.
• Faulty Powertrain/Transmission Control Module (PCM/TCM): → Shop Transmission Assembly This is very rare. The control module should only be considered as the cause after the sensor, harness, and all wiring have been thoroughly tested and confirmed to be good.

Diagnosis Steps

1. Connect a professional OBD-II scanner and confirm P0712 is present.
2. View the live data for the Transmission Fluid Temperature sensor. A reading that is stuck at a very low value (like -40°F) strongly suggests a short circuit.
3. Visually inspect the main transmission electrical connector and wiring harness for any signs of damage, corrosion, or loose connections.
4. Follow the diagnostic procedure outlined in Hyundai TSB 19-AT-019H. This involves testing the circuit to isolate the fault.
5. If the external wiring is confirmed to be good, the fault is internal to the transmission.
6. The next step is to drain the transmission fluid, remove the oil pan, and remove the valve body to access and replace the internal wiring harness assembly.
7. After replacement, refill with the correct specification of automatic transmission fluid (Hyundai SP4-M), clear all codes, and perform an adaptive learning reset with a capable scan tool.

Parts You'll Likely Need

• Transmission Internal Wire Harness Assembly (OEM #46307-4G100) — This is the part specified by Hyundai's TSB to fix the P0712 code. It contains the integrated transmission fluid temperature sensor that fails.
  Trusted brands: Hyundai (Genuine OEM)
  OEM price range: $150-$250
  Aftermarket price range: $100-$180
• Transmission Oil Pan Gasket (OEM #45283-4G100 (Verify with VIN)) — The oil pan must be removed to access the internal harness, and the gasket should be replaced to prevent leaks upon reassembly.
  Trusted brands: Hyundai (Genuine OEM)
  OEM price range: $30-$50
  Aftermarket price range: $20-$40
• Hyundai SP4-M Specification Automatic Transmission Fluid (OEM #00232-19057) — The transmission fluid must be drained to perform the repair and will need to be replaced with 6-7 quarts of fluid that meets OEM specifications.
  Trusted brands: Hyundai (Genuine OEM), Idemitsu TLS-LV, ENEOS Model T-LV
  OEM price range: $20-$30 per quart
  Aftermarket price range: $12-$20 per quart

Related Codes That Often Appear With This One

• P0713 — This code, for 'TFT Sensor Circuit High', is the counterpart to P0712. TSB 19-AT-019H addresses both codes, as they relate to the same component failure (open circuit vs. short circuit).

Technical Service Bulletins (TSBs) & Recalls

• 19-AT-019H: Addresses DTC P071200 and P071300 by instructing technicians to replace the oil pressure harness with the integrated oil temperature sensor for 2020+ Palisade, Santa Fe, and Sonata models.

Platform-Specific Known Issues

• Owner on PalisadeForum.com reported getting P0712 at 75,000 miles. The dealer initially quoted a full transmission replacement before the owner pointed them to TSB 19-AT-019H. The repair was then completed by replacing the internal harness, fixing the issue.
• Multiple owners on both Palisade and Telluride forums confirm that this is a common issue, often occurring between 60,000 and 100,000 miles, and is almost always resolved by replacing the specified internal harness.

Mechanic-Grade Diagnostic Values

• Transmission Fluid Temperature (TFT) Sensor Resistance — expected: Approximately 2.5 kΩ at 20°C (68°F). Resistance decreases as temperature increases.. Failure: A resistance reading near zero ohms indicates a short circuit, which is the direct cause of a P0712 code.
• TFT Sensor Reference Voltage — expected: Approximately 5 volts DC when measured at the harness connector with the key on, engine off.. Failure: A reading significantly below 5V could indicate a short to ground in the wiring harness between the TCM and the transmission, or a faulty TCM.
• TFT Sensor Signal Voltage (Live Data) 🎬 Watch: How to test the TFT sensor circuit — expected: Voltage decreases as temperature rises. A typical range might be ~3.2V at 40°C (104°F) dropping to ~0.29V at 150°C (302°F).. Failure: A signal voltage stuck at a very low value (e.g., under 0.1V) regardless of temperature confirms the 'Circuit Low' condition.

Hidden / Shadow Codes Worth Checking

• P071200: This is the full code format often displayed on the Hyundai GDS (Global Diagnostic System). The '-00' suffix is a component identifier and does not indicate a separate fault, but confirms the code relates to the base P0712 fault. (see via Hyundai GDS or equivalent professional-grade scan tool.)

Scan Tool Commands That Help

• Hyundai GDS (Global Diagnostic System): Resetting Auto T/A Values — This function, also known as resetting adaptive shift values, MUST be performed after replacing the internal harness or valve body. It erases the TCM's learned adjustments, which were based on the faulty sensor data, preventing continued harsh shifting after the repair.
• Hyundai GDS (Global Diagnostic System): Oil pressure characteristics input — While not strictly for the P0712 repair itself, this function is critical if the valve body or entire transmission is replaced. It involves scanning a QR code on the new component to load its specific hydraulic characteristics into the TCM, ensuring proper shift quality.
• Hyundai GDS (Global Diagnostic System): Flight Record — Used for diagnosing intermittent or complex shifting issues. A technician can use this to record live transmission data during a test drive, then analyze the solenoid commands and sensor readings back at the shop to pinpoint anomalies.

Wiring & Ground Locations

• Transmission Connector Pins 9 & 13 — On the main round electrical connector on the transmission case. Pin numbers are often embossed on the connector itself.. On many Hyundai/Kia transmissions, these are the specific pins for the two wires of the TFT sensor circuit. A technician can test resistance directly across these two pins at the transmission connector to isolate the fault to inside the transmission without opening it. This confirms if the internal harness has failed.
• Chassis Ground (Engine Bay) — A common and accessible chassis ground point is a bolt with a silver clip located just below the main under-hood fuse box positive terminal.. When testing for the 5V reference signal at the harness connector, a reliable ground point is needed for the multimeter. Using a known-good, clean chassis ground ensures an accurate voltage reading.

Real Owner Repair Stories

• Reddit user in r/HyundaiPalisade (2020 Hyundai Palisade, 98,000 miles) — Transmission started slipping, RPMs were jumping around, and rough shifting could be felt while driving.
  ✅ What actually fixed it The dealership confirmed the failure and replaced the entire transmission under warranty.

OEM Part Supersession History

• 46307-4G100 → 46307-4G100 — No supersession found.
  Heads up: The part number appears to be consistent across all model years of the Palisade (2020-2024) and other Hyundai/Kia models using the A8LF1/A8MF1 transmission. The lack of a new part number may indicate that the replacement part has not been redesigned to eliminate the original failure mode of the integrated temperature sensor.

Model Year Variations Within This Range

• 2020-2024: The Hyundai Palisade received a significant exterior and interior refresh for the 2023 model year. However, the powertrain, including the Lambda II 3.8L V6 engine and the A8LF1 8-speed automatic transmission, was carried over without major changes. The internal wiring harness (P/N 46307-4G100) that causes code P0712 remains the same part for both pre-facelift (2020-2022) and post-facelift (2023-2024) models.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Tow Hitch Wiring Harness Fire Risk 🔴 High — Affects 2020-2022 models with an accessory tow hitch. Widespread enough to trigger a major recall (NHTSA 22V-633 / Hyundai Recall 235). (Ref: NHTSA Recall 22V-633)
• Excessive Wind/Whistling Noise from Door/Mirror Area 🟡 Low — Common on 2020-2021 models. Many owners report the issue, especially at highway speeds. (Ref: TSB 21-BD-003H, TSB 21-01-003H)
• Unpleasant Interior Odor from Headrests 🟡 Low — Reported on 2020 models with Nappa leather interiors (Limited/Calligraphy trims). Described as a chemical or 'garlic/rotten produce' smell. (Ref: Internal dealer service action (not a formal TSB number released to public))
• Engine Oil Consumption 🟠 Medium — Some owners of the 3.8L V6 report higher than normal oil consumption, sometimes leading to low oil levels between changes. This is a known characteristic of some Hyundai GDI engines.
• Intake Valve Carbon Buildup 🟠 Medium — A long-term issue common to all Gasoline Direct Injection (GDI) engines, including the Lambda II 3.8L. Typically becomes noticeable after 80,000-100,000 miles, causing rough idle or performance loss.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: Never for the internal transmission harness that causes this code. The part has a known high failure rate and the labor cost to install it is significant. The risk of installing a used part that either is already bad or will fail shortly is too high.

What to inspect on the donor part:

• Not applicable. Do not purchase this specific part from a donor vehicle.

OEM-only on this vehicle (don't cheap out):

• Transmission Internal Wire Harness Assembly (P/N 46307-4G100). Due to the high labor cost for installation (3-4.5 hours), the financial risk of a premature failure from a non-OEM part is not worth the small upfront savings. Stick with the Genuine Hyundai part.

Aftermarket brands forum-validated for this vehicle:

• For transmission fluid (SP4-M spec): Idemitsu TLS-LV, ENEOS Model T-LV are widely regarded as reliable alternatives to the OEM fluid.

Brands owners have reported issues with on this vehicle:

• Unbranded or 'white-box' internal wiring harnesses from online marketplaces like AliExpress or eBay. While they may be cheaper, the quality control is unknown, and a failure would require repeating a very expensive labor job.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0713 — This is the companion code to P0712 (High Input vs Low Input) and is addressed by the same TSB 19-AT-019H using the same internal harness replacement procedure.
• P071200 — The specific expanded diagnostic trouble code format used in Hyundai TSB 19-AT-019H to identify the transmission oil temperature sensor circuit low voltage fault.
• P071300 — The specific expanded diagnostic trouble code format used in Hyundai TSB 19-AT-019H to identify the transmission oil temperature sensor circuit high voltage fault.

Frequently Asked Questions