P0135 on the 2020 Honda Odyssey
The 2020 Honda Odyssey uses the 3.5L J35Y7 V6 engine producing 280 horsepower, paired with Honda's 10-speed automatic transmission. The P0135 code indicates the Bank 1 Sensor 1 O2 sensor heater circuit has failed. On the Odyssey's transverse V6, Bank 1 is the rear bank closest to the firewall, and Sensor 1 is the upstream sensor before the catalytic converter. At 4-6 years old, heater element burnout is becoming a possibility on this model year.
Why the Heater Matters on a Family Vehicle
The Odyssey is frequently used for short trips: school runs, grocery errands, and activity shuttles. This driving pattern means frequent cold starts and heater activation cycles. Each cycle stresses the heater element, and the Odyssey's typical usage pattern can accumulate more cycles per mile than highway-focused vehicles. This makes Odyssey O2 sensor heaters particularly prone to premature wear.
Common Causes
- Heater element burnout: The most likely cause at 4-6 years old. The short-trip driving typical of minivans means more cold-start heater cycles than many other vehicles accumulate. The 3.5L V6 also produces significant exhaust heat near the rear bank where the sensor sits.
- Blown heater fuse: The underhood fuse box contains a dedicated O2 heater fuse. Always check this first, as it is a $5 fix that resolves the issue if the fuse is the problem.
- Connector corrosion: The Odyssey's lower clearance and minivan body style can trap moisture near underbody connectors. The rear bank sensor connector is especially vulnerable to road spray and salt in winter climates.
- Wiring damage: The heater circuit wiring behind the engine can degrade from heat soak. The Odyssey's engine bay, with the V6 mounted transversely, can trap heat near the firewall where the Bank 1 sensor wiring runs.
Symptoms
Check engine light is the main symptom. The Odyssey may have a slightly rougher cold start for the first minute or two. Fuel economy on short trips may decrease from the typical 19-28 MPG range. The 10-speed automatic and other vehicle systems are unaffected. Most Odyssey owners notice only the check engine light.
Diagnosis
- Check the O2 heater fuse in the underhood box.
- Disconnect the rear bank upstream sensor and test heater resistance: 2-15 ohms normal, open circuit = failed.
- Verify 12V power at the heater pins with key on.
- Inspect the connector for corrosion, especially if the Odyssey is driven in wet or cold climates.
- Check wiring behind the engine for insulation damage.
Repair Costs
The 2020 Odyssey should be within the federal emissions warranty (8 years/80,000 miles). Out-of-pocket: OEM sensor: $85-$180. Aftermarket: $40-$85. Dealer labor for rear bank: $150-$280. Total dealer: $235-$460. Independent shops: $160-$320. Fuse: under $10.
DIY
The rear bank O2 sensor on the Odyssey is moderately difficult to access due to the V6 filling the engine bay. Working from below may be easier than from above. A 22mm O2 sensor socket with extensions and a universal joint helps. If the sensor has been in place for several years, use penetrating oil overnight. This is a moderate DIY job requiring patience with tight spaces. Always check the fuse first.