: Throwing P0059 and P0155 O2 sensor codes...any advice?



perfect
06-24-10, 04:53 PM
In my 05 CTS-V with 62k miles I have had a CEL for the last few thousand miles. I had it checked out thoroughly today and they came back with 5 codes:

P0059 - HO2S Heater Resistance Bank 2 Sensor 1
P0155 - HO2S Heater Performance Bank 2 Sensor 1
P0803 - 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction (this must be related to my CAGS, right?)
P0059 - HO2S Heater Resistance Bank 2 Sensor 1
P0155 - HO2S Heater Performance Bank 2 Sensor 1

I'm not sure why it came up with 5 codes with 2 of the codes are the same (0059 and 0155).

According to this thread it shouldn't really cause any "damage":
http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/154204-o2-codes.html


Ultimately, my concern sparked because my tire mechanic thought my car had a pretty noticeable misfire. I always assumed that it was my motor mounts being broken (they likely are) and have considered it normal for the last few thousand miles. The engine will shimmy and shake slightly every few revolutions...almost like it has a very mild cam. It wasn't until my mechanic mentioned that he thought he was certain that one of my spark plugs had gone bad did I consider these CEL's to be a problem. Along with the shimmy I've also noticed a decrease in perceived performance over this last year. The car just doesn't feel strong. I don't know what to do and I don't want to throw money hand over first to fix a phantom problem if I don't need to.

What should I do next?

I'm planning on replacing the defective 02 sensor(s) - does 2x codes indicate both sensors are bad? How should I go about checking my spark plugs? Should I just take this to my main mechanic and have him charge me to do everything?

heavymetals
06-24-10, 05:11 PM
On a dead cylinder due to no spark, you can troubleshoot yourself.

I call it the "brute force" method.

You turn off the motor and pull the spark plug wire at the coil end then you get something insulated to hold it with and you start the car (two people is faster). Then you position the end towards the coil entrance and see if you get a spark.

Spark = coil is good, can still be bad wire/connection or plug.

No Spark = coil is funky (if an MSD for sure!).

If it doesn't make a difference on how it idles when you pull the wire, your on the right track.

perfect
06-24-10, 05:17 PM
On a dead cylinder due to no spark, you can troubleshoot yourself.

I call it the "brute force" method.

You turn off the motor and pull the spark plug wire at the coil end then you get something insulated to hold it with and you start the car (two people is faster). Then you position the end towards the coil entrance and see if you get a spark.

Spark = coil is good, can still be bad wire/connection or plug.

No Spark = coil is funky (if an MSD for sure!).

If it doesn't make a difference on how it idles when you pull the wire, your on the right track.

That sounds kind of scary :crying2:

Would a bad spark yield the 02 codes I am getting?

heavymetals
06-24-10, 05:23 PM
It is more then scary if you get bit. :hide:

IT HURTS!

I think you have an air leak.

I would go over all the connections from the airbox to the intake manifold.

(this is from the guy who can't get his own check engine light off, but I have gobs of power and no misfire).

darkman
06-24-10, 05:24 PM
See attached. Based on my reading of these I would not start by throwing parts at it. You may have fuse/wiring/connector/ground problems rather than defective sensors etc.