P0175
System Too Rich (Bank 2)
The engine is getting too much fuel or not enough air on bank 2. The computer cannot correct the mixture back to normal, so it set this code.
- SEV
- 3/5
- DRIVE
- CAUTION
- DIY
- $20–$300
- SHOP
- $150–$800
Quick answer
AI-CITATION READYWhat it means
Can you drive with it?
Most common causes
- Faulty fuel pressure regulator or excessive fuel pressure
- Leaking fuel injector on bank 2
- Dirty or failing mass airflow sensor causing incorrect air measurement
Typical repair cost
DIY usually runs $20–$300. Typical shop repair lands around $150–$800, depending on the root cause.
01 / Definition
P0175 means the engine control module has detected a rich air-fuel condition on bank 2. Fuel trim values have moved negative enough that the PCM is trying to reduce fuel, but the mixture remains too rich. This is usually caused by excess fuel delivery, restricted air intake, incorrect sensor data, or a control fault affecting bank 2.
02 / Drive status
With caution. You may be able to drive short distances, but fuel economy, performance, and emissions can be affected. A very rich condition can damage the catalytic converter if ignored for too long.
03 / Symptoms
- Check engine light
- Poor fuel economy
- Strong fuel smell from exhaust
- Rough idle
- Hesitation or sluggish acceleration
- Black exhaust smoke in some cases
- Hard starting after hot soak
- Failed emissions test
04 / Causes
| 1 | Faulty fuel pressure regulator or excessive fuel pressure | high |
|---|---|---|
| 2 | Leaking fuel injector on bank 2 | high |
| 3 | Dirty or failing mass airflow sensor causing incorrect air measurement | high |
| 4 | Restricted air filter or intake blockage | medium |
| 5 | Faulty engine coolant temperature sensor reading engine too cold | medium |
| 6 | Evaporative purge valve stuck open | medium |
| 7 | Oxygen sensor issue on bank 2 giving false rich readings | medium |
| 8 | Ignition misfire or weak spark causing unburned fuel | medium |
| 9 | Exhaust leak or wiring fault affecting sensor readings | low |
05 / Diagnostic sequence
- 01Scan for related codes and note freeze-frame data, especially fuel trims, coolant temperature, and MAF readings.
- 02Check bank 2 short-term and long-term fuel trims to confirm the engine is running rich.
- 03Inspect the air filter, intake ducting, and throttle body for restriction, contamination, or disconnected hoses.
- 04Check fuel pressure with a gauge and compare it to factory specification.
- 05Inspect bank 2 fuel injectors for leakage, balance issues, or electrical faults.
- 06Clean the MAF sensor with proper MAF cleaner and verify its readings with live data.
- 07Test the purge valve to make sure it is not stuck open.
- 08Verify coolant temperature sensor data matches actual engine temperature.
- 09Check bank 2 oxygen sensor operation and wiring after confirming fuel and air delivery are correct.
06 / Repairs
| 1 | Replace or clean the clogged air filter and repair intake leaks or restrictions | $20–$150 |
|---|---|---|
| 2 | Clean or replace the mass airflow sensor if readings are incorrect | $15–$250 |
| 3 | Repair or replace a faulty purge valve, coolant temperature sensor, or damaged vacuum hose | $50–$300 |
| 4 | Repair leaking fuel injectors or correct excessive fuel pressure from the regulator or pump circuit | $150–$800 |
| 5 | Replace a failed oxygen sensor only after confirming the air-fuel mixture problem is actually fixed | $100–$350 |
07 / Related codes
08 / FAQ
What does bank 2 mean?
Bank 2 is the side of the engine that does not contain cylinder 1 on engines with two cylinder banks.
Can a bad oxygen sensor cause P0175?
Yes, but it is less common than a fuel pressure problem, injector leak, or air measurement issue. The sensor should be tested before replacing it.
Will P0175 clear itself?
It may turn off temporarily if the condition goes away, but it usually comes back until the real cause is fixed.
Can I keep driving with P0175?
Short drives may be possible, but do not ignore it. A rich running condition can waste fuel and damage the catalytic converter.
09 / Source and method
- DATA BASIS
- OBD-II REFERENCE + OBD2.HELP
- METHOD
- STATIC VALIDATION
- SAFETY
- INFORMATIONAL
This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.
Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.
Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.