I've been getting a P0137 code off and on for about a year now. The engine seems to run fine. I've changed out the O2 sensors (#2 on both sides), plugged the bank 1 #2 sensor into the wiring harness for bank 2 #2 and vise versa and the troubled followed the bank 1 #2 sensor. That tells me the wiring to the PCM is good. I cannot find an exhaust leak of any kind. As I stated the engine runs fine, good power and gas mileage so I don't think it's an injector problem.
Does anybody have any other ideas of the cause of this low voltage on the #2 sensor on bank 1 only? THANKS

 

YES...I used to get P0137 after an hour of several rather "heated" runs in the country side due to my after market exhaust set up (see sig below)
....once we installed HP Tuners, My Tuner "tuned it out" as well as all the other P0 codes (137,140,154, etc) relative to the sensors ...these codes do not effect engine performance...they are there to monitor & advise you of the sensor(s) effectiveness.. you can erase that code using the following procedure, but I would suggest you have them turned off (tuned out) as I did:
how to display/erase codes
with the key in the on position, but the engine not running
push and release the reset button until all messages cleared
next push and HOLD button #4
next push and release button #1 four times while holding button #4
When first engaged the on-board diagnostics go into an "automatic" mode which shows all parameters: PCM-TCS-RTD-BCM-IPC-radio-HVAC-LDCM-RDCM-SCM-RFA. If there are no problems, you will see "no more codes" on the ICP display. The computer will show two kinds of codes, "current" and "history," designated "C" or "H". A current code indicates a malfunction is present in the system whose module is displaying data. A history code indicates a past problem. When the screen displays "manual diagnostics," select the desired module by pressing the "options" button to go forward or the "trip" button to go back. Press "gages" to go forward or "fuel" to go back. To exit the diagnostic mode at any time, press "E/M".
If you want to erase or "clear" codes, press .""reset

 

Thanks- I've have been doing the reset--is there anything cheaper than the HP Turners for $499.00?

 

Yep! Find a fellow C5 owner in your area who ownes EFI Live OR HP Tuners. Have them purchase a tuning license for you and have him do the changes for you. I know that the EFI Live License is $100.

Thats the least expensive route. It will also allow you to up-date your tune when you MOD your C5 without further cost.

BC