what is p1151 an how to pepair it

Question

1999 f150 have p1151 code 4.2 engine how can I fix this dont know what to do

Answer 1

HI there,

This code means the rear O2 sensor is not switching from lean to rich and back and forth. Normally the cause for this issue is the rear O2 sensor, however if there is any type of exhaust leak before the sensor or a lean condition in the engine you could get this code as well.