What does the error code PO 138 really mean?

[TheFox]

Ok guys, I was able to jiggle my key back and forth to get the error code for my 2006 PT Cruiser Limited Edition Turbo 2.4 Liter vehicle. However, I have no clue what this code means. Can any of you who have knowledge of these codes, tell me? I've been told that the MIL (engine symbol) does not have to mean anything major. That it could just be a sensor gone bad, and that I might just need a new one. Can you tell me how much this might cost me? If I should go to the service department to get one. I have an extended warranty on my vehicle. But, if this isn't the case and the sensor really is warning me of something, what does this code mean as it relates to my car? Because, I truly do not understand this language or what part of the car this is. Also, recently had an oil change and they used synthetic oil. Would that make a difference? Thanks, to all that reply!

Error Code:

P0138 HO2S Circuit High Voltage Bank 1 Sensor 2

[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.

[Hooligan]

Why even mess with it. You state you have extended warranty, let them fix it.

[TheFox]

Thanks. I know I have an extended warranty. But, I really just wanted to know what the code could have meant?

[TheFox]

Thanks for the response, information, and suggestions that you frequently share with all of us on this site. I really appreciate it. :-)

[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

[CREWZIN]

Travis,

It is a little confusing because in some code charts it reads: P0138 HO2S Circuit High Voltage Bank 1 Sensor 2, and the Sensor 2 means it's the downstream 02 sensor. I went with the explanation from PT Do-It-Yourself.net site because it was put together by mechanics and people that supposedly know what they are doing.

Me, I replaced both at 95,000 miles before either one gave me problems. I definitely believe in preventive maintenance.

[Travis2k7]

Originally Posted by CREWZIN

Me, I replaced both at 95,000 miles before either one gave me problems. I definitely believe in preventive maintenance.

As do I, hence the tranny flush, etc... I did recently.

No biggie, just wanted to point it out that it may or may not be the downstream sensor.

As I recall the upstream sensor was considerably more than the $25 I paid for the downstream... I haven't touched the upstream yet although when the time comes to change the upstream it doesn't appear I'll have to jack up the car as I did with the downstream.