What P0175 Means on Your 2020 Honda Ridgeline
The P0175 code on your 2020 Honda Ridgeline means bank 2 of the 3.5L V6 engine is running rich — there's excess fuel in the combustion mixture. The 2020 Ridgeline uses the J35Y6 3.5L i-VTEC V6 producing 280 hp and 262 lb-ft of torque, the same proven engine found in the Pilot and Odyssey. As a V6, bank 2 refers to the rear cylinder bank (closest to the firewall) with its own O2 sensors and exhaust path. At 4-6 years old, the Ridgeline is in the window where age-related component wear starts causing fuel system codes.
Symptoms on Your Ridgeline
- Check engine light on the dash
- Strong fuel smell from the exhaust, especially at idle
- Rough or unsteady idle
- Black soot accumulation at the exhaust tips
- Fuel economy drops below the rated 18–26 mpg
- Possible misfires under light throttle
Top Causes
1. Degraded Bank 2 O2 Sensor (High Likelihood)
The upstream O2 sensor on bank 2 is the primary fuel control sensor for that cylinder bank. After 4-6 years and 50,000-80,000 miles, the sensor element degrades from thermal cycling, causing slow response or biased readings. If it reads lean, the ECM adds fuel, pushing the actual mixture rich. On the Ridgeline, bank 2 is the rear bank against the firewall, and the sensor sees higher underhood temperatures. Monitor sensor switching speed and compare to bank 1 performance.
2. Leaking Fuel Injector (Medium Likelihood)
The 3.5L V6's port fuel injectors can develop O-ring seal degradation or pintle seating issues over time. A leaking injector on bank 2 (cylinders 1, 2, or 3 on the rear) continuously drips fuel into its intake port. The Ridgeline shares its injectors with the Pilot and Odyssey. Pull bank 2 spark plugs — a fuel-fouled plug identifies the leaking injector.
3. Fuel Pressure Regulator Issue (Medium Likelihood)
The mechanical fuel pressure regulator maintains consistent rail pressure. The internal diaphragm can deteriorate after years of service, causing elevated fuel pressure. Test the vacuum line for fuel contamination and verify rail pressure against Honda's specification of approximately 47-53 psi at idle.
4. Intake or MAF Issue (Low Likelihood)
An overreading MAF sensor or an intake leak that affects the air-fuel calculation can contribute to a rich condition. Since P0175 is bank 2-specific, focus on bank-specific components first. A MAF overreading would typically cause both banks to run rich.
Diagnostic Steps
- Read all codes — P0172 plus P0175 means both banks rich (systemic). P0175 alone means bank 2-specific.
- Compare bank fuel trims — LTFT split between banks confirms bank-specific issues.
- Test bank 2 O2 sensor — Monitor response time and voltage pattern.
- Inspect bank 2 spark plugs — Check for fuel fouling.
- Verify fuel pressure — Test regulator and check for fuel in the vacuum line.
Repair Costs for the Ridgeline
- O2 sensor (bank 2): $120–$290
- Fuel injector: $110–$300 per injector
- Fuel pressure regulator: $130–$290
- MAF sensor: $90–$220
Truck Owner Considerations
The Ridgeline is used for towing, hauling, and sometimes off-road adventures. Running rich under load during towing is especially hard on catalytic converters. If you use your Ridgeline for work or towing, address P0175 before your next hauling job. Catalytic converter replacement on the Ridgeline runs $800-$1,800 per bank — fixing a $120-$290 O2 sensor issue now prevents that expense.
DIY or Shop?
The Ridgeline's engine bay layout mirrors the Pilot's. Bank 1 (front) components are easy to access, but bank 2 (rear) requires more effort. O2 sensor replacement on bank 2 needs an O2 sensor socket, extensions, and possibly working from underneath. Spark plug inspection on bank 2 is tight but doable. For comprehensive fuel system diagnostics, a shop with scan tool capabilities is recommended.