P0135 on the 2017 Honda Accord
The 2017 Honda Accord (9th generation) uses either a 2.4L naturally aspirated K24W (185 hp) or a 3.5L V6 J35Y2 (278 hp). The P0135 code indicates the upstream O2 sensor heater circuit has failed. At 7-9 years old with potentially 70,000-130,000 miles, heater element burnout is a very common and expected issue on the 2017 Accord. On the 2.4L, there is one bank. On the 3.5L V6, Bank 1 is the front bank closest to the radiator.
Why 2017 Accords Get P0135
After years of daily use, the O2 sensor's internal heater wire has endured thousands of heat-up and cool-down cycles. This thermal fatigue causes the resistance wire to develop a thin spot and eventually break open. The 2017 Accord's 2.4L is a well-proven engine that is gentle on sensors, but even so, heater elements are a normal wear item with a typical lifespan of 80,000-120,000 miles.
Causes
- Heater element burnout: The dominant cause on a 2017 Accord at this age. The internal heater wire has reached end of service life. This requires sensor replacement since the heater is not separately serviceable.
- Blown fuse: The O2 heater fuse in the underhood fuse box should always be checked first. A blown fuse is a $5 fix that takes 30 seconds.
- Corroded connector: After years of road exposure, the sensor connector can develop significant corrosion, particularly in rust-belt states. Clean or replace the connector as needed.
- Heat-damaged wiring: The wiring near the exhaust manifold can deteriorate from long-term heat exposure. Brittle insulation can crack and cause shorts or opens.
Symptoms
Check engine light is the primary symptom. At this vehicle age, most owners have enough experience with their Accord to notice the slightly rougher cold-start idle. Fuel economy may drop slightly on short commutes. The biggest practical concern is failing emissions testing, which is required for registration in many states.
Diagnosis
- Check the O2 heater fuse first. This takes 30 seconds and costs nothing.
- Measure heater resistance at the disconnected sensor: 2-15 ohms normal, open circuit = dead heater.
- Verify 12V power at the heater connector with key on.
- Inspect connector for heavy corrosion, especially if the car has been in snowy climates.
- On the 3.5L V6, check the Bank 1 (front) sensor specifically; do not confuse with Bank 2 (rear bank).
Repair Costs
The 2017 Accord is out of basic warranty and likely out of emissions warranty. OEM sensor for the 2.4L: $70-$140. OEM for the 3.5L V6: $80-$170. Aftermarket: $30-$75. Dealer labor: $100-$160 for the 2.4L, $130-$220 for the V6 Bank 1. Total dealer: $170-$390. Independent shops: $110-$260. DIY: sensor cost only.
DIY
The 2.4L Accord has excellent access to the upstream sensor from above the engine. The 3.5L V6 Bank 1 (front) sensor is also reasonably accessible. Use a 22mm O2 sensor socket. Since these sensors have been installed for 7+ years, expect them to be tight. Penetrating oil overnight is essential. Use a breaker bar for initial breakaway. Apply anti-seize to the new sensor threads. Total DIY time: 30-60 minutes.