P0175 on the 2023 Honda Ridgeline
A P0175 code on your 2023 Honda Ridgeline indicates that bank 2 of the 3.5L V6 is running rich. The 2023 Ridgeline continues with the proven J35Y6 3.5L i-VTEC V6 producing 280 hp and 262 lb-ft, now paired with a 9-speed automatic. Bank 2 (the rear cylinder bank) has its own set of fuel injectors, O2 sensors, and exhaust components. On a relatively new vehicle, P0175 usually stems from a premature component failure or factory defect.
Symptoms
- Check engine light on
- Gasoline smell from the exhaust
- Rough or uneven idle
- Black soot at the tailpipe
- Fuel economy below the rated 18–26 mpg
- Possible misfires or stumble
Common Causes
1. Faulty Bank 2 O2 Sensor (High Likelihood)
Even on a 2023 model, a premature O2 sensor failure can occur. If the bank 2 upstream sensor reads falsely lean, the ECM adds fuel to compensate. The bank 2 sensor on the V6 sits in a hot zone near the firewall. Use a scan tool to compare bank 1 and bank 2 sensor performance. A significant difference in switching speed or bias points to the faulty sensor.
2. Leaking Fuel Injector (Medium Likelihood)
The 3.5L V6 uses port fuel injection with individual injectors per cylinder. A manufacturing defect in an injector or its O-ring can cause fuel to drip when the injector should be closed. On bank 2, this enriches cylinders 1, 2, or 3 specifically. Inspect the spark plugs for fuel fouling to identify the affected cylinder.
3. Fuel Pressure Running High (Medium Likelihood)
If the fuel pressure regulator maintains higher-than-normal rail pressure, every injector delivers excess fuel. On a newer Ridgeline, this could be a regulator defect or a software issue. Monitor fuel rail pressure at idle and compare to Honda's specs (approximately 47-53 psi).
4. EVAP System Malfunction (Low Likelihood)
A purge valve stuck open feeds excess fuel vapor into the intake. On a new vehicle, this is a straightforward warranty repair. The symptom is usually a noticeable fuel smell near the engine bay combined with idle surging.
Diagnostic Approach
- Check TSBs — Honda may have published service bulletins for the 2023 Ridgeline.
- Compare bank fuel trims — LTFT differences between banks pinpoint bank-specific issues.
- Test O2 sensors — Compare bank 1 and bank 2 sensor waveforms.
- Check spark plugs — Inspect bank 2 plugs for fuel fouling.
- Verify fuel pressure — Confirm regulator operation.
Cost Estimates
- O2 sensor (bank 2): $120–$300
- Fuel injector: $110–$310
- Fuel pressure regulator: $140–$300
- EVAP purge valve: $80–$190
Warranty Coverage
The 2023 Ridgeline is covered by Honda's 3-year/36,000-mile basic warranty and 5-year/60,000-mile powertrain warranty. O2 sensors are covered under the 8-year/80,000-mile federal emissions warranty. P0175 repairs at a Honda dealer should be free. Don't DIY a warrantied repair — let Honda handle it.
Truck Use With P0175
The Ridgeline is rated for 5,000 lbs towing capacity. Do not tow with an active P0175 code — the added engine load combined with excess fuel delivery puts extreme thermal stress on the bank 2 catalytic converter. For regular commuting, P0175 is safe for a couple of weeks, but schedule your dealer visit promptly.