What causes fault code P0059?

• Most likely: Faulty heater element within the oxygen sensor (Bank 2, Sensor 1) • Likely: High resistance or oxidation in the sensor connector terminals • Possible: Wiring harness damage (frayed wires or short to ground/voltage) • Rare: Faulty HO2S heater relay or internal ECM driver failure

How do you fix fault code P0059?

STEP 1: Inspect the connector at Bank 2, Sensor 1 for moisture, burnt pins, or corrosion. Clean as necessary. STEP 2: Measure the resistance (Ohms) of the heater element. Disconnect the sensor and measure across the heater terminals (usually the two same-colored wires). Normal resistance is typically 5-20 Ohms. Infinite resistance indicates an open heater element. STEP 3: Verify power supply. With the ignition ON, check for 12V at the vehicle-side harness connector. Check the ground circuit, often controlled by the ECU using PWM (Pulse Width Modulation). STEP 4: If wiring and voltage are within specs but sensor resistance is out of range, replace the oxygen sensor (Bank 2, Sensor 1).

Powertrain (Engine & Gearbox)Standard EOBD

P0059 - HO2S Heater Resistance (Bank 2, Sensor 1)

Q: What are the symptoms of fault code P0059?

• Check engine light (MIL) illumination • Decreased fuel economy during warm-up • Slightly rough idle before the engine reaches operating temperature • Failed emissions test

Last updated:1 February 2026

Related:Lambda-sensor (Bank 2, Sensor 1), Engine Control Module (ECM/ECU), Oxygen Sensor, Wiring Harness

System

Powertrain (Engine & Gearbox)

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P0003

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Technical Description

P0059 is an OBD-II generic code indicating that the Engine Control Module (ECM) has detected an improper resistance value in the heater circuit of the upstream heated oxygen sensor (HO2S) for Bank 2. The heater is crucial for bringing the sensor to its operating temperature rapidly to minimize cold-start emissions. The ECM monitors the heater circuit's current draw and voltage drop. If the resistance is found to be outside specific manufacturer tolerances—especially noticed during the 'warm up' phase after a restart—this DTC is stored. This can prevent the fuel system from entering 'Closed Loop' efficiency efficiently.

Possible Causes

Faulty heater element within the oxygen sensor (Bank 2, Sensor 1)

High resistance or oxidation in the sensor connector terminals

Wiring harness damage (frayed wires or short to ground/voltage)

Faulty HO2S heater relay or internal ECM driver failure

Symptoms

Check engine light (MIL) illumination

Decreased fuel economy during warm-up

Slightly rough idle before the engine reaches operating temperature

Failed emissions test

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P0059 - HO2S Heater Resistance (Bank 2, Sensor 1)

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P0059 - HO2S Heater Resistance (Bank 2, Sensor 1)

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