O2 Sensor Heater Resistance High (Bank 2, Sensor 1)
The P0059 code indicates that the powertrain control module (PCM) has detected a high resistance in the heater circuit of the oxygen sensor located before the catalytic converter on bank 2 (the side opposite cylinder #1). The heater element is essential for the sensor to reach operating temperature quickly, especially during cold starts. High resistance reduces current flow, causing slow sensor response and potentially affecting fuel trim and emissions.
01. Most Common Causes
- Faulty oxygen sensor (bank 2, sensor 1)
- Open or shorted heater circuit wiring
- Blown fuse for O2 sensor heater
- Corroded or loose connector at the sensor
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Rough idle or hesitation during cold start
- Decreased fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0059 and check freeze frame data.
Step 2: Visually inspect the O2 sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure resistance between the heater circuit pins at the sensor connector; compare to manufacturer specs (typically 2-10 ohms).
Step 4: Check for battery voltage and ground at the heater circuit with the ignition on; repair open or short as needed.
Step 5: If all wiring and voltage are okay, replace the oxygen sensor (bank 2, sensor 1).
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail an emissions test and fuel economy may suffer. Prolonged driving could damage the catalytic converter.
How much does it cost to fix?▼
Typically $150-$300 for parts and labor, depending on vehicle make and sensor accessibility.