Ask Andy AIP0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
What it means, what causes it, and what it costs to fix.
What P0135 means
Oxygen sensors have a built-in heater so they work right after a cold start. The heater in the bank 1 upstream sensor has failed, or its circuit has a problem.
Can I drive with P0135?
Severity: Low. Not urgent. Fix it when convenient.
Safe to drive. Mileage and emissions may suffer until the sensor warms up on its own.
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Ask Andy about P0135Symptoms
- Check engine light
- Slightly worse fuel economy
Common causes
Most likely first.
- Burned-out heater inside the O2 sensor (most common)
- Blown O2 heater fuse
- Damaged wiring near the exhaust
How to diagnose P0135
- Check the O2 heater fuse.
- Measure heater resistance across the sensor's heater pins. Open means the sensor is bad.
- Inspect the harness for melted spots near the exhaust.
Tip: most US auto parts stores will read your codes for free.
Repair costs
| Fuse | $1–$10 |
| O2 sensor | $150–$350 installed |
Typical US prices. Your vehicle, region, and shop rates will change these.
P0135 FAQ
What does P0135 mean?
P0135 means "O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)." Oxygen sensors have a built-in heater so they work right after a cold start. The heater in the bank 1 upstream sensor has failed, or its circuit has a problem.
Can I drive with a P0135 code?
Safe to drive. Mileage and emissions may suffer until the sensor warms up on its own.
What is the most common cause of P0135?
The most common cause is: Burned-out heater inside the O2 sensor. Other causes include blown o2 heater fuse and damaged wiring near the exhaust.
How much does it cost to fix P0135?
Typical repairs run about $1 to $350 in the US, depending on the cause. Fuse: $1–$10.
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