Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn LW200, 2002 Saturn L200, and 2002 Saturn L100. However, it is still accessible from the selected car via links, so may be relevant.
Ensure HO2S2 is tight in exhaust pipe. A ground path must exist between exhaust pipe and engine block. Add a ground wire between exhaust manifold and engine head if resistance is more than 10 ohms. DTC may set if no ground path exists.
Ensure no exhaust leaks exist between HO2S1 and 18" after HO2S2. An exhaust leak in that area will cause false HO2S2 readings and may set DTC. Repair as necessary.
A misfiring cylinder(s) pushing raw fuel out exhaust port will damage converter over time. Verify that no current or history misfire counts exist in any failure record.
Replace catalyst.