P0135: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
Can you still drive? Yes, the vehicle is safe to drive. The main impact is poor fuel economy and higher emissions during the warm-up period.
What Does P0135 Mean?
Code P0135 indicates a malfunction in the heater circuit of the upstream oxygen sensor on bank 1. Modern oxygen sensors contain a heater element that brings the sensor to operating temperature quickly after engine start. If the heater circuit fails, the sensor takes much longer to become active, resulting in poor fuel control during warm-up.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Failed O2 sensor heater element
- Blown fuse for O2 sensor heater circuit
- Corroded wiring or connector
- Faulty relay controlling heater circuit
- ECM driver failure in rare cases
Symptoms
- Check engine light on
- Poor fuel economy during warm-up
- Rough idle when cold
- Increased emissions during warm-up
Diagnostic Steps
- 1Check fuse for oxygen sensor heater circuit
- 2Measure heater element resistance with multimeter
- 3Verify 12V power supply to sensor heater
- 4Inspect wiring harness and connector for damage
- 5Check ground circuit continuity
Recommended Parts & Tools
upstream oxygen sensor
electrical connector cleaner
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $100 - $350 |
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Chat with AI About P0135Commonly Affected Vehicles
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Frequently Asked Questions
What does the O2 sensor heater do?
The heater element brings the oxygen sensor to its operating temperature of about 600 degrees Fahrenheit quickly, so the engine can enter closed-loop fuel control sooner after starting.
Can a blown fuse cause P0135?
Yes, always check the fuse first. It is a free and easy fix that could save you the cost of a new sensor.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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