What P0135 Means for Your 2020 Traverse
Your 2020 Chevrolet Traverse has logged a P0135 diagnostic trouble code, indicating a problem with the oxygen sensor heater circuit on Bank 1, Sensor 1. The 2020 Traverse comes standard with GM's 3.6L V6 engine (310 hp), which uses a transverse-mounted layout. On this V6, Bank 1 is typically the rear cylinder bank (closer to the firewall), and Sensor 1 is the upstream O2 sensor before the catalytic converter.
At 4-5 years old, your Traverse may be experiencing early sensor wear or an ongoing issue that's just now triggering a code. The O2 sensor heater is designed to bring the sensor to operating temperature within seconds, allowing quick transition to efficient closed-loop fuel control.
Symptoms You're Likely Noticing
- Steady check engine light
- Slightly decreased fuel economy
- Rough idle during cold starts
- Extended warm-up before smooth operation
- Emissions test failure
Most Traverse owners report the SUV drives fine once warmed up. The heater circuit issue primarily affects cold-start behavior and fuel efficiency on short trips.
Common Causes of P0135 on the 2020 Traverse
O2 Sensor Heater Element Failure
The internal heater element degrades from thermal cycling over time. The 3.6L V6 runs at normal operating temperatures, but the heater element still experiences significant stress during each cold-start cycle. At 50,000+ miles, early heater failure can occur.
Connector Corrosion
The O2 sensor connector is exposed to heat and road conditions. Corrosion on heater circuit pins can cause intermittent or complete heater failure. This is common in regions with road salt or high humidity.
Wiring Damage
The sensor wiring routes near hot exhaust components. Heat damage, rubbing, or rodent damage can compromise the heater circuit wiring.
Blown Fuse
The O2 heater circuit fuse can blow, disabling the heater. This is a quick check that rules out one possibility immediately.
Warranty Considerations
Check your 2020 Traverse warranty status:
- Bumper-to-Bumper: 3 years/36,000 miles (likely expired)
- Powertrain: 5 years/60,000 miles (may still apply)
- Federal Emissions: 8 years/80,000 miles for certain components
Contact your Chevrolet dealer to verify coverage before paying for repairs. The O2 sensor may qualify under emissions warranty.
Diagnosis Steps
- Check warranty first—Could save you money
- Scan for all codes—Note any companion codes
- Inspect the fuse—Quick and free
- Check connector—Look for corrosion or damage
- Test heater resistance—Should be 2-30 ohms
- Verify power supply—Battery voltage should reach heater circuit with key on
Repair Costs
Professional Repair
- Dealer: $200-$350
- Independent shop: $150-$280
- Diagnostic fee: $80-$150 (often applied to repair)
DIY Approach
- OEM AC Delco sensor: $80-$140
- Quality aftermarket: $50-$100
- O2 sensor socket: $15-$25
DIY Replacement Guide
The upstream O2 sensor on the 2020 Traverse V6 can be accessed from above on the rear bank, though access is tight. The transverse engine layout makes sensor access more challenging than longitudinal V6 applications.
- Work with a cold engine
- Locate Bank 1 Sensor 1 on the rear exhaust manifold
- Disconnect electrical connector first
- Apply penetrating oil to sensor threads
- Use O2 sensor socket with wire slot
- Remove sensor (may require extensions and universal joints)
- Apply anti-seize to new sensor threads
- Install and torque to spec (30-40 ft-lbs)
- Clear codes and verify repair
V6 Bank Location Note
The 3.6L V6's transverse mounting means Bank 1 and Bank 2 are oriented front-to-back rather than left-to-right. Bank 1 is typically the rear bank (firewall side). If you're doing the repair yourself, verify the sensor location with a service manual or scan tool that shows live data.
Prevention Tips
- Use Top Tier gasoline
- Address oil consumption issues promptly
- Don't ignore other engine codes
- Plan for O2 sensor replacement around 100,000 miles