Jeep 2002, 4.0 L, 120K has a Trouble code PO456 and Pending code PO442
Peter’s question:
Hi, Jeep 2002, 4.0 L, 120K has a Trouble code PO456 and Pending code PO442 – Evaporative Emission System. The MIL is ON. What do you recommend me to do? Thank you, Peter ”
Answer:
Those are both codes for small evap system leaks–The hardest ones to find. They can be REALLY small. The only way to even attempt to find them is to hook up a smoke machine to the evap system and search for leaks.Check for hose connection leaks, the evap pressure sensor for leaks, the evap cannister purge valve (a very common problem in jeeps), and the evap cannister itself for leaks. The larger leaks are pretty easy to catch, but those small ones can be absolute monsters. Good Luck,
