OBD-II Generic Error Code P0173: How to Fix It

Q: What is the difference between P0171 and P0173?

P0171 is for bank 1, P0173 is for bank 2. Engine banks are numbered; bank 1 contains cylinder #1. Both indicate fuel trim malfunctions.

Q: Can a dirty MAF sensor cause P0173?

Yes, a dirty MAF sensor can cause incorrect air intake readings, leading to a lean condition and triggering P0173.

Q: Is it safe to drive with code P0173?

It may be safe for short distances, but prolonged driving can damage the catalytic converter or cause poor performance. It's best to diagnose and fix promptly.

Q: What are common symptoms of P0173?

Common symptoms include rough idle, poor acceleration, reduced fuel economy, check engine light, and possible misfire.

Q: Can a vacuum leak cause both P0171 and P0173?

If the leak is in a common area (like the intake manifold or PCV system), it can affect both banks and set both codes.

Abstract

Error code P0173 means that the fuel trim system on engine bank 2 is malfunctioning, indicating a lean or rich condition. This usually points to a vacuum leak, faulty oxygen sensor, or fuel system issue.