P0175 on the 2021 Hyundai Palisade V6
The 2021 Hyundai Palisade is powered by the Lambda II 3.8L GDI V6 producing 291 hp and 262 lb-ft of torque, paired with an 8-speed automatic transmission. This engine uses gasoline direct injection with dual continuously variable valve timing (D-CVVT). Bank 2 on the Lambda II V6 is the rear cylinder bank (closest to the firewall). P0175 indicates the ECM has detected that this bank is running persistently rich.
Symptoms
- Check engine light on
- Fuel economy below the rated 19-26 MPG
- Rough idle or vibration
- Black exhaust smoke during acceleration
- Reduced power, especially noticeable with a full load of passengers
- Fuel smell from exhaust area
Top Causes on the Lambda II 3.8L GDI
1. GDI Carbon Buildup on Intake Valves (High Likelihood)
The Lambda II 3.8L GDI is particularly susceptible to carbon buildup on the intake valves. At 40,000-70,000 miles typical for 2021 models, carbon deposits can be significant. As a family hauler, the Palisade often makes short trips (school runs, grocery runs) in city driving, which accelerates carbon accumulation because the engine doesn't reach and maintain temperatures needed to burn off deposits. Carbon buildup disrupts airflow and combustion, directly affecting fuel trim on Bank 2.
2. MAF Sensor Contamination (High Likelihood)
The 3.8L V6 draws substantial airflow through the MAF sensor. Years of PCV oil vapor and environmental contaminants coat the hot-wire element. On the Palisade, the engine bay layout positions the intake near heat sources, which can accelerate PCV vapor production. A contaminated MAF underestimates airflow, leading to over-fueling. Clean with MAF sensor cleaner as the cheapest first step.
3. Bank 2 O2 Sensor Degradation (Medium Likelihood)
The upstream O2 sensor on Bank 2 (rear exhaust manifold) monitors exhaust gas composition for fuel trim correction. At 40,000-70,000 miles, the sensor may show early signs of degradation. The rear bank position on the Palisade receives less cooling airflow, potentially accelerating sensor aging. Test response time with a graphing scan tool.
4. GDI Injector Carbon Fouling (Medium Likelihood)
The direct injectors on Bank 2 operate inside the combustion chamber at high pressures. Carbon can accumulate around the injector tips, affecting spray patterns and preventing proper sealing. This compounds the intake valve carbon issue. Professional injector cleaning or replacement may be needed alongside valve carbon cleaning.
V6 Bank-Specific Diagnosis
When P0175 appears without P0172, the issue is isolated to Bank 2 (rear bank). This narrows the diagnosis to the rear bank O2 sensor, rear bank injectors, or the rear exhaust manifold area. If both codes appear together, the cause is system-wide (MAF sensor, fuel pressure, or intake air issue).
Diagnostic Steps
- Scan all codes. Check for P0172 to determine bank-specific vs. system-wide issue.
- Check recall status and TSBs for the Lambda II 3.8L.
- Monitor Bank 2 fuel trim data. LTFT below -10% confirms enrichment.
- Clean the MAF sensor first.
- Test Bank 2 upstream O2 sensor response time.
- Borescope Bank 2 intake valves for carbon assessment.
Repair Costs
MAF cleaning: $10-$15. MAF replacement: $130-$290. O2 sensor: $170-$350. Carbon cleaning (walnut blast) for V6: $500-$800. GDI injector replacement: $250-$450 per injector. Diagnostic time: $100-$160/hour.