P0135 on the 2016 Honda Civic
The 2016 Honda Civic was the first year of the 10th generation, available with a 2.0L naturally aspirated R20A (158 hp) or the new-for-2016 1.5L turbocharged L15B7 (174 hp). At 8-10 years old with potentially 80,000-150,000 miles, the P0135 code is a very common maintenance issue. The O2 sensor heater element has simply worn out from years of thermal cycling, and this is completely normal for a sensor of this age.
Why 2016 Civics Commonly Get P0135
The O2 sensor heater is activated every time you start the engine. Over 8+ years, that amounts to thousands of heat-up and cool-down cycles on a small resistance wire inside the sensor. The wire eventually develops a thin spot and breaks, creating an open circuit. The 2016 Civic's 1.5T was the first year of Honda's new turbo engine, and early production sensors may have slightly shorter heater lifespans due to the hotter exhaust environment.
Common Causes
- Heater element burnout: The overwhelmingly most common cause on a 2016 Civic. At this age and mileage, the heater wire has simply reached end of life. Replacing the sensor resolves the issue.
- Blown heater fuse: Always check the fuse first. It is in the underhood fuse box and costs under $1 to replace. If it keeps blowing, there is a short in the wiring.
- Connector corrosion: After nearly a decade of road use, especially in salt-belt states, the sensor connector can develop significant corrosion that disrupts the heater circuit.
- Wiring deterioration: Years of heat exposure near the exhaust can cause wiring insulation to become brittle and crack, leading to shorts or open circuits.
Symptoms
Check engine light is the main indicator. At this vehicle age, many owners are accustomed to the car's behavior and may not notice the subtle cold-start roughness or slight fuel economy decrease. The biggest practical impact is failing an emissions test, which prevents registration renewal in many states.
Quick Diagnosis
- Check the heater fuse in the underhood box. If blown, replace ($1) and monitor.
- Disconnect the O2 sensor and check heater resistance with a multimeter: 2-15 ohms is normal, open circuit means burned out.
- Check for 12V at the heater power wire with key on.
- Inspect the connector for heavy corrosion, especially if the car has been in northern states.
- If the heater is burned out, replace the entire sensor. The heater is not separately serviceable.
Repair Costs
The 2016 Civic is very affordable to repair. OEM Denso sensor: $70-$140. Aftermarket (Bosch, NGK): $30-$70. Dealer labor: $100-$160. Total dealer: $170-$300. Independent shop: $100-$200 total. DIY cost: $30-$140 for the sensor only. The 2016 Civic is likely outside both the basic and emissions warranty, so out-of-pocket cost is expected.
DIY Instructions
This is one of the easiest repairs you can do on a 2016 Civic. The upstream sensor is clearly visible and accessible from the top of the engine bay. Tools needed: 22mm O2 sensor socket (or a deep 22mm socket and wrench), and penetrating oil. Important: since this sensor has been in place for 8+ years, it will likely be seized. Soak it with penetrating oil the night before. Use a breaker bar for initial torque. Anti-seize the new sensor threads. Total time: 30-60 minutes including soak time.