F 150 4WD Pickup V8-5.4L CNG VIN M (2001)

P0120 - P0124: Testing and Inspection
P0121
For diagnosis of code P0121 refer to chart
Bxxxx, Cxxxx, P0102 - P0171
If there is no link in the chart then:
-
This code is not a valid code for this vehicle
-
Or information published by the manufacturer for this vehicle did not include this code