Porsche Error Code P1129: How to Fix It

Q: What causes Porsche P1129 error code?

P1129 is typically caused by vacuum leaks, faulty oxygen sensors, dirty or faulty MAF sensor, clogged fuel injectors, low fuel pressure, dirty air filter, or intake manifold gasket leaks. It indicates the engine is running too lean on Bank 2.

Q: Can I drive my Porsche with P1129 code?

While P1129 is not immediately dangerous, continued driving with this code can cause engine damage over time due to the lean condition. It may also cause poor fuel economy, rough idle, and potential engine knock. Address the issue promptly.

Q: How much does it cost to fix P1129 on a Porsche?

Repair costs vary widely depending on the root cause. Simple fixes like replacing an air filter ($30-50) or cleaning the MAF sensor ($20-40) are inexpensive. More complex repairs like oxygen sensor replacement ($200-400) or fuel injector service ($300-600) cost more.

Q: Will P1129 clear itself after fixing the problem?

P1129 will not clear automatically. You must use an OBD2 scanner to clear the code after completing repairs. The code may return if the underlying problem isn't properly fixed or if there are additional issues.

Q: Which bank is Bank 2 on a Porsche engine?

On most Porsche engines, Bank 2 refers to the passenger side (right side when facing the engine) cylinder bank. Bank 1 is typically the driver's side. However, this can vary by model, so consult your service manual for confirmation.

Abstract

Porsche error code P1129 indicates a Long Term Fuel Trim Multiplicative lean condition on Bank 2 of your engine. This means your engine's computer is detecting that the air-fuel mixture is too lean (too much air, not enough fuel) and is trying to compensate by adding more fuel.