code P 1131 & P1131PD

[burt ragio]

A friend has a 1999 Grand Marquis. Codes came up after replacing two primary cat on left & right bank. Code P1131 & P1131PD. Any idea what codes mean ?

[Pat]

P1131's are oxygen senor related. This particular code means lack of upstream heated oxyen senso switch, sensor indicaes lean, bank 1.

See link for topic discussion. WWW.engine-light-help.com (http://www.engine-light-help.com)

Since this happened after the cats were changed did a wire break underneath the car, maybe the O2 sensor was damaged.

Sometimes these codes are tripped by another component malfunctioning and the O2 sensor pick up the result. The Mass Air Flow Sensor could have malfunctioned.