Nissan: P155b-00

If your Nissan has triggered this code, don’t ignore it. Diagnose promptly, replace the faulty valve, and get back on the road with confidence. Disclaimer: This article is for informational purposes only. Always consult a professional mechanic or your vehicle’s service manual for model-specific procedures. Vehicle repairs should be performed by qualified individuals following safety guidelines.

While you might be able to drive a few miles to a repair shop, continuing to drive with a stuck-closed bypass valve risks serious engine damage. Overheating can warp cylinder heads, blow head gaskets, or even seize the engine—all of which cost thousands to repair versus a few hundred for a valve replacement. nissan p155b-00

So, what exactly is ? Is it serious? Can you still drive your car? And most importantly, how much will it cost to fix? If your Nissan has triggered this code, don’t ignore it

Modern Nissan engines (notably the QR25DE in Altimas and Rogues, and the VQ series in Pathfinders) use a sophisticated cooling system. Instead of a simple thermostat, many use a to manage engine temperature more precisely. Always consult a professional mechanic or your vehicle’s

A: No. The code specifically targets the bypass valve, not the main thermostat. However, replacing both components together is often good preventative maintenance.