[Travis2k7]

Originally Posted by CREWZIN

There's couple of reason why you got that code but it should mean that something wrong with the upstream 02 sensor.




You can try replacing it yourself, or have a mechanic put a scanner on your PT and pinpoint the exact problem. This is from PT Do-It-Yourself.net ....

P0138 -1/2 O2 Sensor Shorted To Voltage - Oxygen sensor input voltage maintained above normal operating range.

Possible causes:

Intermittent Condition
O2 Sensor Operation
O2 Sensor Signal Shorted To Voltage
O2 Sensor Signal Open
O2 Sensor Ground Circuit Open
PCM

1/2= O2 sensor before the cat.
2/2= O2 sensor after the cat.

Not sure if the code definition changes between the NA and Turbo models but a few months back when I was getting P2097 and P0138 codes, the printout I got from Autozone said it was the downstream O2 sensor at the cat.

It was $25 to replace it, and I reset the codes which haven't come back since.

Edit:

Found this too.

P0138 HO2S Circuit High Voltage Bank 1 Sensor 2