Codes P0050, P0059, and P0155 2010 Yukon Denali XL

[Marcustomer]

I’ve had this truck for 6 months or so, I bought it due to the lower mileage, around 95k to replace our 07. That said, the 07 was more trouble free than this one has been. This is the latest, three these three codes last week.
050 says Heater Control circuit Bank 2 Sensor

059 Heater Resistance Bank 2 Sensor

155 02 Sensor Heater Circuit Bank 2

Also just noticed that the auxiliary fan comes on at start up, not sure if it’s due to our air temps finally getting a little warmer (60’s) or tied to this issue. I’m guessing it’s just an 02 Sensor but would appreciate feedback. Thanks in advance

 

[gooffeyguy]

Those codes are all for the O2 sensor.
Bank 2 sensor 1, which is passenger side front (pre-cat) sensor.

My aux or high speed fan has been coming on also when started and the hvac set to AUTO and 72 inside the last couple of days

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Big Mama]

^^X2 no big deal. You may want to consider all of them but 1 will hold you for now. 30 minute job.

 

[BG1988]

I’ve had this truck for 6 months or so, I bought it due to the lower mileage, around 95k to replace our 07. That said, the 07 was more trouble free than this one has been. This is the latest, three these three codes last week.
050 says Heater Control circuit Bank 2 Sensor

059 Heater Resistance Bank 2 Sensor

155 02 Sensor Heater Circuit Bank 2

Also just noticed that the auxiliary fan comes on at start up, not sure if it’s due to our air temps finally getting a little warmer (60’s) or tied to this issue. I’m guessing it’s just an 02 Sensor but would appreciate feedback. Thanks in advance

Very detailed information from (the code are the same for non hybrids excluding hybrid based codes)
https://gsi.ext.gm.com/gmspo/mode6/pdf/2010/10OBDG10 Hybrid Diagnostics.pdf

p0050 OS2 HeaterControl Circuit bank 2 sensor 1 Voltage low during driver open state (Indicates short to ground or open circuit ) or voltage high during driver closed state (indicates short to voltage)
P0155 O2S heater performace bank 2 sensor 1

 

[swathdiver]

I’ve had this truck for 6 months or so, I bought it due to the lower mileage, around 95k to replace our 07. That said, the 07 was more trouble free than this one has been. This is the latest, three these three codes last week.
050 says Heater Control circuit Bank 2 Sensor

059 Heater Resistance Bank 2 Sensor

155 02 Sensor Heater Circuit Bank 2

Also just noticed that the auxiliary fan comes on at start up, not sure if it’s due to our air temps finally getting a little warmer (60’s) or tied to this issue. I’m guessing it’s just an 02 Sensor but would appreciate feedback. Thanks in advance

Before you spend any money, crawl underneath and check the wiring on the O2 sensor and the after the connection into the wiring harness. A few guys with these codes have found chafed wires that were shorting out. Worst case its the ECM.

 

[Marcustomer]

Wow, thank you all for the feedback! Very impressive! I’ll check under the truck today as Swathdiver suggested. I’ll report back with feedback. Thanks!!

 

[07YukonCornelius]

Before you spend any money, crawl underneath and check the wiring on the O2 sensor and the after the connection into the wiring harness. A few guys with these codes have found chafed wires that were shorting out. Worst case its the ECM.

This happened to me. Apparently the clamp on the CV boot on the front driveshaft at the xfer case ripped the wires out of the drivers side downstream O2 sensor & the fuel level sensor. I bought new connectors but all the new wires are WHITE. Now I don’t know which wire goes where. I’ve tried to google an image but haven’t had any luck. Does anyone have a pic of the O2 connection? If I have that I think I can narrow down the wires that go to the fuel level sensor.
thanks.

 

[wsteele]

This happened to me. Apparently the clamp on the CV boot on the front driveshaft at the xfer case ripped the wires out of the drivers side downstream O2 sensor & the fuel level sensor. I bought new connectors but all the new wires are WHITE. Now I don’t know which wire goes where. I’ve tried to google an image but haven’t had any luck. Does anyone have a pic of the O2 connection? If I have that I think I can narrow down the wires that go to the fuel level sensor.
thanks.

I can try and find the O2 sensor pinouts in my shop manual. Failing that, I can probably crawl under the truck tomorrow and take some pictures of the connectors, wires in and out, etc.

 

[07YukonCornelius]

I can try and find the O2 sensor pinouts in my shop manual. Failing that, I can probably crawl under the truck tomorrow and take some pictures of the connectors, wires in and out, etc.

Sweet!
Thank You!

 

[wsteele]

Sweet!
Thank You!

I will keep looking in the manual for the connector pinouts. I also have the old O2 sensors that I took out recently when I changed all 4 and clearly can take pictures of the wire colors from the sensor to the connectors and what position on that connector it goes to. I will probably have to crawl under to get pictures of the wire colors and where they go from the PCM to the sensor. I will let you know tomorrow (assuming the colors may be different on each side of the connector).

Is it only the downstream you need?