What does the P0455 code mean for a Jeep Grand Cherokee?

So, I’ve been dealing with this Evap code, P0455, for a year now on my 2003 Jeep Grand Cherokee with a 4.7 engine. I’ve tried smoke testing it four times, replaced the leak detection pump, several hoses, and even got two new gas caps. Finally, it looks like I’ve fixed it, and I wanted to share what worked for me: the PCV hoses! They’re hidden behind the valve covers, and on mine, all three soft hoses had cracks. It took me using a flashlight and a mirror to finally spot them, and even then, it was tough. But, I replaced them with about $20 worth of hose and an hour’s work, and it seems to have solved the problem!

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hi arthur the P0455 code for a Jeep Grand Cherokee signals a large leak in the Evaporative Emission Control System (EVAP). This system prevents fuel vapors from escaping into the atmosphere.

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There’s a sense of accomplishment in resolving a persistent car issue on your own, especially when the solution turns out to be relatively inexpensive. Fixing the cracked PCV hoses on your 2003 Jeep Grand Cherokee and addressing the P0455 Evap code is a significant achievement.

Why your experience is valuable to others encountering similar challenges:

  1. P0455 Culprit Isn’t Always Obvious: Your journey involved various troubleshooting methods, such as smoke testing and replacing common Evap system components, before pinpointing the PCV hoses. This underscores that identifying Evap leaks can be elusive and requires determination.
  2. PCV Hoses as a Potential Cause: Sharing your experience sheds light on the fact that faulty PCV hoses can contribute to Evap system leaks and trigger P0455 codes. This awareness can assist others in diagnosing their own issues.
  3. DIY Repair with Minimal Cost: Your ability to rectify the problem independently using affordable parts showcases that certain car repairs are feasible for DIY enthusiasts, minimizing expenses in the process.

The meaning of the P0455 code in a jeep is that it indicates a “Large Evaporative Emission Control System Leak Detected.” This diagnostic trouble code (DTC) is set when the engine control module (ECM) detects a large leak in the evaporative emissions system, which is responsible for preventing fuel vapors from escaping into the atmosphere.