P0455 on a Jeep Wrangler
P0455 means evaporative Emission System Leak Detected (Large Leak). On the Wrangler, a few causes come up far more than others.
What P0455 usually means on a Wrangler
P0455 is a large evaporative-emissions leak on the Wrangler, meaning the sealed fuel-vapor system is losing containment in a big way. The most common trigger by far is a loose, worn, or cross-threaded gas cap, followed by the purge and vent valves. Wranglers also crack vapor lines over time, and the fuel-filler area is a known trouble spot on these rigs. It will not affect how the Jeep drives, but it keeps the check-engine light on and fails emissions.
Most common causes on the Wrangler
- Loose or worn gas cap
Tighten to several clicks and inspect the seal; a bad cap is the number-one P0455 cause.
- Stuck-open purge valve
A purge solenoid that will not seal leaks the system and sets a large-leak code.
- Vent valve fault
A vent valve stuck open keeps the system from holding vacuum during the self-test.
- Cracked EVAP hose or filler-neck issue
Aged vapor lines and the fuel-filler area are known leak points on Wranglers.
What P0455 costs to fix on a Wrangler
If a gas cap fixes it, the cost is trivial. Valves and hoses are inexpensive parts, so most of any bill is the smoke-test diagnostic time, usually a modest few hundred dollars at most. This is a take-your-time repair with no drivability risk.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Wrangler owners also ask
Why does my Wrangler keep throwing P0455 after I replaced the gas cap?
Either the new cap is not sealing on a worn filler neck, or the leak is elsewhere, commonly a purge or vent valve or a cracked vapor hose. A smoke test will pinpoint it rather than leaving you swapping caps repeatedly.
Can water crossings cause EVAP codes on a Wrangler?
Wading itself should not, but water and grit can accelerate corrosion and wear on EVAP valves and connections over time. If codes appear after heavy off-road use, have the vapor lines and valves inspected.
Other codes on the Jeep Wrangler
Related symptoms
Jeep Wrangler problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0455 behavior is covered on the main P0455 page. Confirm with a scan tool before buying parts.
P0455 on your Wrangler?
Every problem becomes a Case. Tell Redline what your Wrangler is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.