What P0175 Means on Your 2021 Honda HR-V
The P0175 code on your 2021 Honda HR-V indicates bank 2 is running rich — too much fuel relative to air. The 2021 HR-V (2nd generation) uses the R18Z 1.8L i-VTEC naturally aspirated four-cylinder engine producing 141 hp and 127 lb-ft of torque, paired with a CVT. This is a relatively simple, port-injected engine that's proven reliable, but fuel system issues can still arise. As an inline-four, the P0175 bank 2 reference relates to the ECM's secondary fuel trim monitoring.
Symptoms You'll Notice
- Check engine light on the dash
- Fuel smell from the exhaust
- Rough or slightly uneven idle
- Black soot at the tailpipe
- Fuel economy drops below the rated 28–34 mpg
- Engine may stumble during acceleration
Common Causes on the 2021 HR-V
1. O2 Sensor Issue (High Likelihood)
The oxygen sensors on the 2021 HR-V's 1.8L engine monitor exhaust gas for fuel trim corrections. A sensor that reads falsely lean — from contamination, slow response, or internal degradation — causes the ECM to add extra fuel. At 3-5 years of service, premature sensor failure is possible but not common on Honda's reliable 1.8L. Use a scan tool to monitor sensor voltage oscillation — a healthy sensor switches between 0.1V and 0.9V several times per second.
2. Leaking Fuel Injector (Medium Likelihood)
The 1.8L's port fuel injectors are simple, reliable units, but O-ring seals can deteriorate over time. A leaking injector allows fuel to drip into the intake port when it should be sealed. Pull the spark plugs and inspect for fuel fouling — a wet, black plug identifies the problem cylinder. Port injectors for the HR-V are affordable at $40-$80 each.
3. Fuel Pressure Regulator Malfunction (Medium Likelihood)
The mechanical fuel pressure regulator on the 1.8L engine uses a diaphragm to maintain consistent rail pressure. If the diaphragm deteriorates, fuel pressure rises and all injectors deliver excess fuel. The classic diagnostic test: check the vacuum line from the regulator for fuel. Also measure fuel rail pressure — it should be approximately 40-47 psi at idle.
4. Stuck EVAP Purge Valve (Low Likelihood)
A purge valve stuck in the open position continuously feeds fuel vapor into the intake manifold. On the HR-V, this would create a noticeable fuel smell near the engine and may produce surging at idle. Command the purge valve on and off with a scan tool to verify operation.
How to Diagnose P0175
- Scan for all codes — Check for P0172 (bank 1 rich) and misfire codes.
- Monitor fuel trims — LTFT below -10% confirms the ECM is actively cutting fuel.
- Test O2 sensor — Check voltage oscillation speed and range.
- Inspect spark plugs — Look for fuel fouling.
- Check fuel pressure — Verify regulator performance and check for fuel in the vacuum line.
Repair Costs for the 2021 HR-V
The HR-V is one of Honda's most affordable vehicles to repair:
- O2 sensor replacement: $80–$200
- Fuel injector replacement: $80–$220 per injector
- Fuel pressure regulator: $100–$250
- EVAP purge valve: $70–$170
DIY Friendly
The 2021 HR-V's 1.8L engine bay is compact but accessible. O2 sensor replacement is a straightforward beginner-level DIY job. Spark plug inspection takes 15-20 minutes. Port fuel injectors on the 1.8L are easily accessible and can be swapped with basic hand tools. The fuel pressure regulator is also accessible. Overall, P0175 diagnosis and repair on the HR-V is very DIY-friendly.
Should You Worry?
P0175 isn't a critical code, but fix it within two weeks. Running rich wastes fuel, fouls spark plugs, and gradually damages the catalytic converter. Catalytic converter replacement on the HR-V runs $400-$900 — far more than fixing the root cause. The 1.8L is a reliable engine, and resolving P0175 typically returns it to perfect operation.