libertybob
Full Access Member
I had to disconnect the driver side cat and crossover exhaust pipe (one piece on 2003 Liberty's after 2/2/2003) to change the transmission. I re-installed the original starter with 173k miles when re-assembling the vehicle. Upon startup I got the P0420 cat efficiency code at about 30-50 mile intervals. I thought this strange as I never had this code until changing the transmission. Murphy's Law, the starter failed after 200 miles so the cat and crossover pipe had to come out again to get the starter out since my Liberty is a 4x4. Also had to remove the front drive shaft. Put in a re-manufactured starter and when re-installing the cat and crossover pipe I used my transmission jack to hold the cat/crossover pipe tight against the driver side exhaust manifold and installed the clamp tight, then re-installed the bolts on the passenger side cat, nuts on the pipe support bracket, and nuts on the muffler flange. No more P0420 codes. On the first installation of the cat/crossover pipe I bolted up the passenger cat, muffler, and support bracket first and then the driver side cat at the exhaust manifold. I theorize that I must have had a small leak at the driver side manifold causing the throwing of Code P0420. So the starter problem saved me from buying new cats. Seems the cats are sensitive to exhaust leaks so check this if you have cat codes.
