2004 GMC Yukon xl

SAMTHMAN

MEMBER
2004 GMC YUKON
V8
AWD
AUTOMATIC

I have a 2004 GMC Yukon Denali Xl, and pulled service codes p154 and p155. The description was Bank 2 Sensor 1. I changed both(upstream) and cleared the codes. I then went for a drive, and at about the 24 mile mark. The check engine light came on again. When I checked. The same codes came up. What did I do wrong?

6 Replies

WRENCHTECH

MECHANIC
20,758 POSTS

What you did wrong was to assume that those codes meant the sensors are causing the problem. That's not necessarily the problem. The codes merely indicate a situation that the PCM has detected. Now you have to figure out what the cause was. It's not as simple as read a code and change a part as so many people believe.

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Friday, November 19th, 2010 AT 11:34 PM

SAMTHMAN

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I kinda figured that. I had my Denali since it was new and I had it serviced at the dealer up until recently. I'm no tech, but I'm pretty good with my hands. I just need some guidance. Is there anything else you need to know to help me?

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Friday, November 19th, 2010 AT 11:46 PM

WRENCHTECH

MECHANIC
20,758 POSTS

Check all your fuses and look the harness over carefully for any breaks or burns. Those are 2 different codes both referring to the same sensor so the wiring would be highly suspect. You have both a heater code and a signal code. They are separate circuits and that has to be more than a coincidence.

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Friday, November 19th, 2010 AT 11:50 PM

SAMTHMAN

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8 POSTS

Wow. I will give it a looksee tomorrow, and let you know. While I have your attention. My driver's side window only works when the ignition key's in the accessary position. I hooked up a snap on flash computer to run a test, and it didn't tell me anything. Do you think it's the module in the door or the door switch?

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Friday, November 19th, 2010 AT 11:56 PM

WRENCHTECH

MECHANIC
20,758 POSTS

That's a subject for a new question. We can't address multiple problems or multiple vehicles in the same thread. It gets way too hard to follow, especially if another expert gets involved.