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P0135 on 2020-2025 Kia Telluride: O2 Sensor Heater Circuit Causes and Fixes

This code means the heater inside the upstream oxygen sensor on the rear exhaust manifold (Bank 1) has failed. The most common fix is to replace the Bank 1, Sensor 1 O2 sensor. Expect to pay $70-$180 for the part, with a DIY difficulty of 2/5.

17 minutes to read 2020-2025 Kia Telluride

Most Likely Cause

Failed Bank 1, Sensor 1 Oxygen Sensor

Difficulty

2/5

Est. Time

0.8 hrs

DIY Doable?

✅ Yes

Shop Labor

$120 – $280

Parts Price

$70 – $180

⚠️ Drivable, but... — Yes, the vehicle is drivable, but you should get it fixed soon. The engine will run less efficiently, especially when cold, leading to increased fuel consumption and higher emissions. Ignoring it long-term could potentially shorten the life of the catalytic converter, a much more expensive repair.

Key Takeaways

P0135 points directly to a problem with the heater circuit for the upstream O2 sensor on the rear exhaust manifold (Bank 1).
The most likely cause is a failed oxygen sensor that needs to be replaced. The OEM part number is 39210-3L110.
Before buying a new sensor, always check the 'SENSOR 1' and 'SENSOR 4' fuses in the engine bay fuse box—it's a cheap and easy check.
Also, visually inspect the sensor's wiring for any signs of melting or damage, as it is close to the hot exhaust.
This is a DIY-friendly repair for those with basic tools, but you will need a special slotted socket to remove and install the oxygen sensor.

The trouble code P0135 indicates that the Engine Control Module (ECM) has detected a malfunction in the heater circuit of the Bank 1, Sensor 1 oxygen sensor. Oxygen sensors must be very hot (around 600°F) to produce an accurate signal. A built-in electric heater brings the sensor to operating temperature quickly after a cold start to minimize emissions and ensure proper fuel control. This code is set when the ECM determines the heater is not working correctly, due to an open circuit, a short, or improper electrical resistance.

What's Unique About the 2020-2025 Kia Telluride

For the Kia Telluride, the P0135 code does not indicate a unique platform-specific defect but rather a common type of oxygen sensor failure. The Lambda II 3.8L V6 is a modern GDI engine, but the diagnostic process for this heater circuit code follows standard automotive troubleshooting. Bank 1 is the cylinder bank closer to the firewall (the rear bank), and Sensor 1 is the upstream sensor located in the exhaust manifold before the catalytic converter. Its platform-mate, the Hyundai Palisade, shares the same engine and experiences the same P0135 failures.

🎬 Watch: A detailed breakdown of the P0135 code on Kia vehicles.

Symptoms You May Notice

Check Engine Light is on.
Decreased fuel economy.
Vehicle may run slightly rough or hesitate during the first minute after a cold start.
Failing an emissions test.

⚠️ Don't Waste Money on the Wrong Fix

Replacing the wrong oxygen sensor (e.g., Bank 2 sensor on the front manifold, or the downstream Sensor 2 after the catalytic converter).
Replacing the oxygen sensor without first checking for a blown fuse or inspecting the wiring for damage.

Most Likely Causes

Failed Bank 1, Sensor 1 Oxygen Sensor 🔴 High Probability The internal heater element is a common failure point in all modern oxygen sensors due to constant, rapid heat cycles. This is the most frequent cause for P0135.
How to confirm: After confirming power and ground at the sensor connector, test the resistance across the two heater circuit pins on the sensor itself using a multimeter. An infinite reading (open circuit) or a reading far outside the typical 2-20 ohm range confirms failure.
Typical fix: Replace the Bank 1, Sensor 1 (rear, upstream) oxygen sensor. A special slotted oxygen sensor socket is often required for removal and installation. 🎬 Watch: How to replace an upstream oxygen sensor step-by-step.
Est. part cost: $70-$180
Damaged Wiring or Connector 🟡 Medium Probability The sensor wiring is located near the hot exhaust manifold, making it susceptible to heat damage, melting, or becoming brittle over time. Road debris can also physically damage the harness.
How to confirm: Visually inspect the wiring harness and connector leading to the sensor for any signs of melting, chafing, corrosion in the pins, or loose connections. Check for continuity on the heater circuit wires between the ECM and the sensor connector.
Typical fix: Repair the damaged section of wiring or replace the connector pigtail.
Est. part cost: $15-$50
Blown Fuse ⚪ Low Probability An electrical short in the heater circuit can cause the corresponding fuse to blow as a protective measure. This is often a symptom of a failed sensor shorting out.
How to confirm: Locate the fuse for the O2 sensor heater circuit in the vehicle's engine compartment fuse box. On the Telluride, this is labeled 'SENSOR 1' (10A) or 'SENSOR 4' (15A), which powers multiple sensors. Visually inspect if it is blown.
Typical fix: Replace the blown fuse. If the new fuse blows immediately, it indicates a persistent short circuit in the wiring or within the oxygen sensor itself that must be found and fixed.
Est. part cost: $1-$5

Rare But Worth Checking

Faulty Engine Control Module (ECM): This is extremely rare. The ECM's internal driver for the heater circuit can fail. This should only be considered after all other possibilities (sensor, wiring, fuse) have been definitively ruled out by testing.

Diagnosis Steps

Connect an OBD-II scanner to confirm P0135 is the active code.

🎬 See these easy first checks to diagnose the heater circuit.

Consult a fuse diagram to locate and inspect the fuse for the O2 sensor heater circuit in the engine compartment fuse box. On the Telluride, check the 'SENSOR 1' (10A) and 'SENSOR 4' (15A) fuses. Replace if blown.
Safely raise the vehicle and locate the Bank 1, Sensor 1 oxygen sensor on the rear exhaust manifold (closer to the firewall).
Visually inspect the sensor's wiring harness and connector for any signs of melting, chafing, corrosion, or loose pins.
Disconnect the sensor. With the key on and engine off, use a multimeter to verify there is 12-volt power and a good ground connection on the harness-side of the connector (on the two heater circuit pins).
Using the multimeter, measure the resistance between the two heater circuit pins on the sensor itself. A reading of infinite ohms indicates an open circuit and a failed sensor. A reading between 2.5-20 ohms is typically considered normal for Kia/Hyundai vehicles.
If the fuse, wiring, power, ground, and sensor resistance all check out, the problem may lie in the wiring between the connector and the ECM, or (rarely) the ECM itself.
After repair, clear the code with the scanner and perform a test drive, including a cold start, to ensure the code does not return.

Parts You'll Likely Need

Bank 1, Sensor 1 Oxygen Sensor (OEM #39210-3L110) — This is the upstream oxygen sensor for the rear cylinder bank (Bank 1). Its internal heater element is the most common failure point that triggers code P0135. This part is also referred to as the Front Left sensor.
Trusted brands: Genuine Kia/Hyundai, NGK/NTK, Denso, Bosch
OEM price range: $120-$200
Aftermarket price range: $70-$150

Mechanic-Grade Diagnostic Values

O2 Sensor Heater Element Resistance — expected: 2.5 to 20 Ω (Ohms). Failure: A reading of infinite ohms (open circuit) or a value significantly outside the expected range.
Heater Circuit Power Supply — expected: 12V (Battery Voltage) with Key On, Engine Off. Failure: 0V or significantly low voltage, indicating a wiring or fuse issue before the sensor.

Scan Tool Commands That Help

Kia GDS (Global Diagnostic System): O2 Sensor Data / Heater Circuit Test — The GDS tool can be used to monitor live data from the oxygen sensor and may offer a specific function to actively test the heater circuit, confirming if the ECM is commanding the heater on and if the sensor is responding. This is useful for differentiating between a sensor failure and a control-side (ECM/wiring) issue.

Wiring & Ground Locations

Engine Compartment Fuse Box — Located in the engine bay, typically on the driver's side.. This box contains the fuses that supply power to the oxygen sensor heater circuits. For the P0135 code, the 'SENSOR 1' (10A) and 'SENSOR 4' (15A) fuses are the primary ones to inspect, as a blown fuse will cut power to the heater and trigger the code.
Bank 1 Sensor 1 Connector — Attached to the upstream oxygen sensor on the rear exhaust manifold (closest to the firewall).. This is the primary point for electrical testing. The connector for this specific sensor is a 5-pin, oblong shape with a flat side. Technicians test for 12V power, ground, and signal at this connector's harness side, and test for resistance on the sensor side pins.

OEM Part Supersession History

39210-3L110 → No known supersession. — N/A
Heads up: No supersession is noted in parts catalogs. When ordering, it is critical to ensure the part is 39210-3L110 for Bank 1 (Left/Rear) and not 39210-3L100, which is for Bank 2 (Right/Front).

Model Year Variations Within This Range

2023-2025: The Kia Telluride received a cosmetic facelift for the 2023 model year, including new grille, lighting, and interior screens. However, the core powertrain, the 3.8L Lambda II GDI V6 and 8-speed automatic transmission, remained unchanged. Therefore, the causes, diagnosis, and repair for a P0135 code are identical across the entire 2020-2025 model year range.

Diagnostic Flowchart

Start by confirming the P0135 code (Bank 1 Sensor 1 Heater Circuit) is active. This flowchart guides you through electrical testing of the Lambda II 3.8L V6's rear upstream sensor.

Locate the engine compartment fuse box. Are the 'SENSOR 1' (10A) or 'SENSOR 4' (15A) fuses blown?

→ Replace the blown fuse. If it blows again immediately, there is a short circuit in the wiring harness or the internal heater element of the Bank 1 Sensor 1 O2 sensor.

Access the Bank 1 Sensor 1 (rear manifold near firewall). Is there visible damage to the harness or connector?

→ Repair the damaged wiring or replace the connector pigtail. Ensure the harness is routed away from the hot exhaust manifold to prevent future melting or heat-soak brittleness.

Disconnect the sensor. With Key On Engine Off (KOEO), does the harness-side connector show 12V power and a solid ground on the heater circuit pins?

→ The issue lies in the wiring between the fuse box/ECM and the sensor. Check for open circuits or high resistance in the vehicle's main engine harness.

Using a multimeter, measure resistance across the two heater pins on the sensor itself. What is the reading?

→ The internal heater element has failed. Replace the Bank 1, Sensor 1 oxygen sensor using a slotted O2 sensor socket. This is the most common failure for the Telluride/Palisade platform.

The sensor tests electrically sound. Does this 3.8L GDI engine show signs of the known 'Excessive Oil Consumption' issue (1qt per 1,000-2,500 miles)?

→ Excessive oil consumption can coat the sensor in carbon, causing intermittent heater circuit performance. Clean the sensor or replace it, and perform an oil consumption test at a Kia dealer.

→ If the sensor, wiring, and fuses are all verified, the fault may be a software glitch or a rare ECM failure. Check for any available ECM updates related to emissions logic before replacing the controller.