P0442 on Jeep: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Small Leak)
1 Jeep model · 1 documented issue · $25-$350 repair
P0442 on Jeep by model: symptoms, diagnosis and fix
P0442 (small EVAP leak, roughly a 0.020–0.040 inch pinhole) is very common on the WK2 Grand Cherokee. The two dominant causes are a degraded gas cap rubber seal and, specific to this platform, a failed Evaporative System Integrity Module (ESIM) mounted in the rear driver-side wheel well. The ESIM is a well-documented WK2 failure point and often fails before other EVAP components; it is known to pass a smoke test yet still set the code because its internal switch fails to report the correct state to the PCM. A vapor canister purge valve stuck slightly open is a secondary cause. There are typically no drivability symptoms beyond the check engine light, and the code can be intermittent (may clear after a few good drive cycles once the cap is tightened).
Common Symptoms
- Check engine light on
- Intermittent fuel/vapor smell (rare)
- No noticeable drivability change
- Occasional gas cap warning
How to Fix
Start with a new OEM Mopar gas cap and confirm it clicks/seals; clear the code and drive several cycles. If it returns, replace the ESIM in the rear driver-side wheel well (accessed behind the fender liner, on the charcoal canister). If still present, smoke-test the EVAP system to find hose/purge-valve/canister leaks.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar evaporative-system integrity module (ESIM) for the confirmed 2016-2018 branchOEMMopar 68505622AA
Confirm the VIN, fuel-system configuration, connector and current part before purchase; it is not approved across the ful
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Sources for this issue (4)
P0442 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0442 mean on a Jeep?
P0442 stands for "Evaporative Emission Control System Leak Detected (Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it. On Jeep it is documented across 1 model: Grand Cherokee.
What are the most common causes of P0442?
The most common causes of P0442 are: Loose, damaged, or missing fuel filler cap, Worn or cracked gas cap seal, Cracked or disconnected EVAP hose or line, Faulty purge valve or vent valve, Damaged O-ring or seal at the fuel tank or filler neck, Small crack in the charcoal canister, Leaking fuel tank sending unit gasket. The specific cause varies by vehicle.
How much does it cost to fix P0442 on a Jeep?
Published repair estimates on Jeep range from $25 to $350 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.