OBD-II Code · Fuel & Air
P0175
System Too Rich (Bank 2)
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$50–$500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
MAF cleaning first
Bank 2 running rich.
How a shop works this
Rich is the mirror of lean: the ECU is pulling fuel out and the sensor still reports rich. The scan data tells you which side of the system is putting the extra fuel in.
Read short-term and long-term fuel trim, warm, at idle, on the affected bank.
Positive means the ECU is adding fuel, negative means it is taking fuel away. Read short-term and long-term together rather than either on its own. As a rule of thumb rather than a specification, correction beyond roughly plus or minus 10% is worth chasing. Sustained negative correction is the signature here.
Check the things that add fuel the ECU did not ask for.
A leaking or dripping injector, fuel pressure above spec from a failed regulator, and an evaporative purge valve stuck open are the common three. A purge valve stuck open is usually at its worst right after a fill-up.
Check the things that make the engine measure less air than it is getting.
A dirty or failing MAF reporting low, and a restricted air filter, both make the ECU over-fuel for the airflow it thinks it has. A rough sanity check at warm idle is around 1 gram per second per litre of displacement — near 2 on a 2.0-litre four, near 5 on a 5.0-litre V8. Displacement and conditions move it a lot, so treat it as a smell test rather than a spec.
Read the plugs before ordering parts.
Black, sooty plugs confirm the engine really is running rich rather than the sensor reporting it wrongly. Clean plugs on a rich code move suspicion to the sensor or its wiring.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Black smoke
- Fuel smell
- Check engine light
- Poor fuel economy
Likely causes
- Leaking injector bank 2Most common
- Fuel pressure issue
- Dirty MAF
- Faulty O2 sensor bank 2
Read the full diagnostic procedureP0175 is the bank-2 'rich' code — too much fuel for the air entering bank 2, with LTFT pulled past -25% trying to lean things back out.
P0175 is the bank-2 'rich' code — too much fuel for the air entering bank 2, with LTFT pulled past -25% trying to lean things back out. Diagnosis collapses into the same logic as P0172 but isolated to one bank, which is actually useful because anything wrong upstream of both banks (global fuel pressure, contaminated MAF, failed canister purge venting into the common plenum) tends to throw P0172 and P0175 together — when only P0175 sets, the cause is mechanically scoped to bank 2.
Cheapest checks first
- clean the MAF with sensor-safe spray (P0175 alone from a MAF is rare but worth ruling out at $12), then pull and inspect the bank-2 spark plugs — soot-black, sooty deposits on every plug on that bank is direct confirmation the bank is running rich, and clean ceramic on bank 1 with sooty bank 2 plugs is the diagnostic photograph.
- Next, scope or noid-test the bank-2 injectors looking for one stuck open or with degraded pintle return — a single leaking injector dumps fuel continuously into one cylinder and drives the whole bank rich.
- Finally check the bank-2 upstream O2 sensor: a sensor with a slow switching response or stuck near 0.9V can fool the ECU into the wrong direction.
- Black smoke from the tailpipe at idle plus a strong gasoline smell at the bank-2 exhaust manifold is the field signature.
Vehicle-specific patterns2002-2008 Dodge Ram 1500 / Durango with the 4.7L V8 commonly throws P0175 from a leaking #6 or #8 injector (bank 2 on this engine) that sticks open a…
- 2002-2008Dodge Ram 1500 / Durango with the 4.7L V8 commonly throws P0175 from a leaking #6 or #8 injector (bank 2 on this engine) that sticks open at idle — Bosch makes the OEM injector and replacing it as a set on that bank is the durable fix.
- 2003-2007Cadillac CTS / SRX with the 3.6L LY7 V6 throws P0175 from a failed evaporative-purge solenoid that vents fuel vapor into the bank-2 intake during cold operation.
- 2007-2013GMC Acadia / Buick Enclave / Chevy Traverse with the 3.6L LLT direct-injection V6 throws P0175 from carbon-coked injectors on the bank-2 side — a chemical decarbon plus injector replacement is common around 100k miles.
- 2000-2006Mercedes E320/CLK320/SLK320 with the M112 V6 throws P0175 from a failed bank-2 air-mass meter or stuck-open purge valve. Repair cost typically $50-$500 — MAF cleaning at the low end, injector replacement at the high end ($300-$500 for a single OEM injector + labor).
Look up another code
P0175 — frequently asked
What does a P0175 code mean?
Bank 2 running rich.
What causes a P0175 code?
Common causes: Leaking injector bank 2; Fuel pressure issue; Dirty MAF; Faulty O2 sensor bank 2.
What are the symptoms of a P0175 code?
Typical symptoms: Black smoke; Fuel smell; Check engine light; Poor fuel economy.
Is it safe to drive with a P0175 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $50-$500 — MAF cleaning first.
How do I diagnose a P0175 code?
Rich is the mirror of lean: the ECU is pulling fuel out and the sensor still reports rich. The scan data tells you which side of the system is putting the extra fuel in. 1. Read short-term and long-term fuel trim, warm, at idle, on the affected bank. 2. Check the things that add fuel the ECU did not ask for. 3. Check the things that make the engine measure less air than it is getting. 4. Read the plugs before ordering parts.
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