Component Location Index
CATALYTIC CONVERTER
Removal/Installation
POWERTRAIN CONTROL MODULE (PCM)
General Troubleshooting information
Replacement
DTC Troubleshooting
DTC P0420: Catalyst System Efficiency Below
Threshold
NOTE:
Before you troubleshoot, record all f
1. Remove the piston from the engine block.
2. Using a ring expander (A), remove the old piston
rings (B).
3. Clean all ring grooves thoroughly with a squared-off
broken ring or ring groove cleaner with a blade
to fit the piston grooves.
The top and 2nd ring grooves are 1.2 mm (0.05 in.)
wide. Th