P0175: System Too Rich (Bank 2)

P0175 means the air-fuel mixture on Bank 2 is too rich and the ECU cannot remove enough fuel to bring it back to the 14.7:1 stoichiometric target. Because the code is bank-specific, the cause is usually something local to Bank 2 (a leaking injector on that side, a degraded sensor, or fuel pressure imbalances) rather than a whole-engine issue.

P0175 is a fuel system-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0175 and illuminates the check engine light.

If your vehicle has triggered P0175, you may notice one or more of these symptoms:

• Check engine light on
• Reduced fuel economy
• Strong fuel smell from the exhaust
• Black soot at the tailpipe outlets, sometimes only on one side
• Rough idle and possible cylinder-bank misfires

Here are the most common causes of P0175, ranked by how likely they are to be the culprit:

Generally yes, for short-term driving. Short-term driving is safe, but a rich-running bank wastes fuel, fouls plugs on that side, and gradually damages the catalytic converter on Bank 2. Fix within a couple of weeks to avoid catalyst replacement costs.

Follow these steps to pinpoint the root cause of P0175:

1. Read live data: confirm Bank 2 long-term fuel trim is negative beyond -20% while Bank 1 stays within normal range
2. Pull Bank 2 spark plugs and inspect for black sooty deposits. Compare to Bank 1 plugs; a clear visual difference confirms the bank-specific richness
3. Swap the upstream lambda sensors between Bank 1 and Bank 2. If the rich condition follows the sensor, replace it
4. Measure fuel pressure with a gauge and compare to spec at idle and under load. High pressure can over-fuel both banks but sometimes shows up more on the bank with already weak injectors
5. Perform an injector balance test or have injectors flow-tested off the engine. A single leaking injector on Bank 2 explains the code on a V6 or V8

Repair costs for P0175 vary depending on the root cause and your vehicle. Here are typical estimates:

P0175 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:

These codes are often seen alongside P0175 or indicate related issues: