DTC P0420, P0421, P0430, P0431: Catalyst Efficiency Monitor Malfunction

WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Catalyst Efficiency Monitor Malfunction Troubleshooting Procedure (1 Of 2)

Courtesy of FORD MOTOR CO.

Fig 2: Catalyst Efficiency Monitor Malfunction Troubleshooting Procedure (2 Of 2)

Courtesy of FORD MOTOR CO.

Fig 3: Catalyst Efficiency Monitor Malfunction Inspection Procedure (1 Of 6)

Courtesy of FORD MOTOR CO.

Fig 4: Catalyst Efficiency Monitor Malfunction Inspection Procedure (2 Of 6)

Courtesy of FORD MOTOR CO.

Fig 5: Catalyst Efficiency Monitor Malfunction Inspection Procedure (3 Of 6)

Courtesy of FORD MOTOR CO.

Fig 6: Catalyst Efficiency Monitor Malfunction Inspection Procedure (4 Of 6)

Courtesy of FORD MOTOR CO.

Fig 7: Catalyst Efficiency Monitor Malfunction Inspection Procedure (5 Of 6)

Courtesy of FORD MOTOR CO.

Fig 8: Catalyst Efficiency Monitor Malfunction Inspection Procedure (6 Of 6)

Courtesy of FORD MOTOR CO.