2003 Jeep Wrangler - Code 442 (check engine light) Evaporation Leak

This is an evap code for a leak in the system. Quick check would be the gas cap.make sure it's a tight fit and s slso ck for any nicks on the filler opening, where you put the gas pump into fill gas, sometimes s small dent, scratch, nick won't allow cap to seal and cause vacuum leak when e.c.u tries to do it's test.if at any time you have a gas smell, this would be an indication of a evaporation leak fuel leak and cause this code.the only proper way to find an evap leak wo

(M) Check Engine Light ("Malfunction Indicator Light" or "Check Engine") will illuminate during engine operation if this Diagnostic Trouble Code was recorded (depending if required by CARB and/or EPA). MIL is displayed as an engine icon on the instrument cluster.

P0351 (M)
Ignition Coil A Primary/Secondary Circuit
Peak primary circuit current not achieved with maximum dwell time.

P0420 (M)
Catalyst System Efficiency Below Threshold (Bank 1)
Catalyst 1/1 efficiency below required level.

P0442 (M)
Evaporative Emission Control System Leak Detected (medium leak)
A 0.040 leak has been detected in the evaporative system. (A faulty gas cap may cause this code). Also see TSB 25-001-02A. Note: The respective Powertrain Diagnostic Procedures Manual will direct the technician to determine if the vehicle evaporative system has an external system leak. Examples of some external system leaks are: a loose gas cap, a disconnected evaporative system hose, or a loose hose connection. Remember that the evaporative system may also have an internal system leak. This internal leak may be caused by an intermittent or permanently stuck open Duty Cycle Purge (DCP) valve. This leak source is considered to be internal because any escaping emissions enter into the engine system and not directly into the atmosphere, unlike an external leak. An internal leak may cause one of the above DTC?s. Possible causes of a stuck open (intermittent or permanent) DCP valve are: 1. Corrosion due to system moisture or possible water intrusion into the system.

P0455 (M)
Evaporative Emission Control System Leak Detected (large leak)
A large leak has been detected in the evaporative system. See TSB 25-001-02. Also, possible faulty or loose gas cap. Note: The respective Powertrain Diagnostic Procedures Manual will direct the technician to determine if the vehicle evaporative system has an external system leak. Examples of some external system leaks are: a loose gas cap, a disconnected evaporative system hose, or a loose hose connection. Remember that the evaporative system may also have an internal system leak. This internal leak may be caused by an intermittent or permanently stuck open Duty Cycle Purge (DCP) valve. This leak source is considered to be internal because any escaping emissions enter into the engine system and not directly into the atmosphere, unlike an external leak. An internal leak may cause one of the above DTC?s. Possible causes of a stuck open (intermittent or permanent) DCP valve are: 1. Corrosion due to system moisture or possible water intrusion into the system.

Please follow the ink for information on this code.

P0442 Ford Evaporative Emission System Leak Detected Small Leak

You can fix it very much yourself. Just get an online manual here for like 10-15$ and you need no mechanic.


It's one of those manuals people get nowadays to do it yourself.. My nephew use it to repair my car and it's totally repaired now. Here's the website he bought it from. 2002 jeep liberty Very good website

NOPE CANT ERASE CODES UNTIL THE PROBLEM IS FIXED OR THE SERVICE ENGINE LIGHT SOON WILL STAY ON. CODE PO441 - EVAPORATIVE EMISSION EVAP SYSTEM INCORRECT FLOW DETECTED.CHECK INTAKE VACUUM HOSE CONNECTIONS AT THE EVAP CANISTER PURGE VALVE.IF ALL IS GOOD.THE EVAP CANISTER PURGE VALVE COULD BE BAD. CODE PO 442 - EVAPORATIVE EMISSION EVAP SYSTEM SMALL LEAK DETECTED. EVAPORATIVE EMISSION SYSTEM LARGE LEAK DETECTED FUEL CAP LOOSE OR OFF MISSING. CODE PO 446 - EVAPORATIVE EMISSION EVAP SYSTEM VENT CONTROL CIRCUIT MALFUNCTION.

Small emission leak would indicate to me that the exhaust is leaking, maybe, throwing off the O2 sensor.

If it's an evaporative leak, then I would make sure the gas cap is on tight, and that the filler tube is connected with a vapor tight connection to the tank, and that the tank has no leaks in it.

What was the code, exactly, if I might ask?

here is an overview of the evap system. as stated in the article, large leaks are due to a faulty or loose gas cap or cracked or disconnected vapor line. http://www.aa1car.com/library/evap_system.htm

a fuel cap indication would mean a leak not nessesaraly your gas cap, id check the fuel neck vent hose for a leak

most likely the pressure sensor in the fuel tank for the evap system is defective.

Found on my jeep that the high quality vac line to the evap bottle had split on the under side.