1537..

[BigWaveDave]

ok folks i have a 1537 with the key on engine off.The cars running fine and i have new o2 sensors.Last i had codes there ws this tiny t shaped vacumn hose in the rear of the motor that had self destructed.

 

[Tiltedhalo]

1537

1537 is IMRC stuck open bank 1, if you have a Gen1 i would check the vac line, and replace.