| Subject: | Revised DTC P0420 Catalyst System Low Efficiency | 
| Models: | 1996-2001 Chevrolet/Geo Metro | 
| 1996-2004 Chevrolet/Geo Tracker | 
| 1996-1997 Pontiac Sunrunner | 
| 1996-2001 Pontiac Firefly | 
Built with the following engines:
Engine  | Model Year  | Model  | 
|---|---|---|
1.0L Engine VIN 6 -- RPO LP2  | 1996-2000  | Chevrolet/Geo Metro Pontiac Firefly  | 
1.3L Engine VIN 9 -- RPO L72  | 1997  | Geo Metro Pontiac Firefly  | 
1.3L Engine VIN 2 -- RPO LY8  | 1998-2001  | Chevrolet Metro Pontiac Firefly  | 
1.6L Engine VIN 6 -- RPO L01  | 1996-1997  | Pontiac Sunrunner  | 
1996-2002  | Chevrolet/Geo Tracker  | |
2.0L Engine VIN C -- RPO L34  | 1999-2004  | Chevrolet Tracker  | 
2.5L Engine VIN 4 -- RPO LE8  | 2001-2004  | Chevrolet Tracker  | 
This bulletin is being issued to revise Step 8 of DTC P0420 Catalyst System Low Efficiency in the Engine Controls sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.
The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.
Step  | Action  | Values  | Yes  | No  | 
|---|---|---|---|---|
8  | 
 Important: Before installing the replacement converter, locate and repair the cause of the TWC converter failure. Replace the three-way catalytic converter and the warm-up three-way catalytic converter (WU-TWC), if equipped. Is the action complete?  | --  | Go to Step 10  | --  |