Battery drain, knock sensors and constant efans= PCM corrosion

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Dad28

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Augusta Kansas
New guy here. 2005 Yukon SLT, 5.3 gas, RWD. 241,000 miles

I wanted to thank everyone on this forum for the great sharing of information and share with you mine in hopes of it helping someone else.

My wife went out to go to the store the other morning and her battery was completely dead. Would not jump nor hold a charge. Only a year old so I went and bought a new one and returned the dead one.

She said that it ran fine the night before. When I put in the new battery, the efans turned on automatically when I attached the negative terminal. This seemed odd since the car had notbeen running for 18 hours andtthe engine was cold. I don't have experience with efans, however, so I first thought it was probably a bad temperature sensor that turned on the fans and drained the battery.

I started it up and immediately got codes 0332 and another for emissions. The emissions code is ongoing and I ignore it. The other code was knock detector. The car was running horribly, with what seemed like misfiring and bucking while in park. It seemed odd that it would go from running completely fine to having a knock issue by sitting in the driveway turned off overnight.

I shut it off and started researching on here. Possibilities included bad knock sensors, knock sensors wiring, relays, fuses, and numerous other things. I looked at YouTube videos and googled it all as well. Through a combination of ideas, possibilities and diagnosis, somewhere I came across the possibility of water or corrosion in the PCM plug.

Longer story short, I pulled the PCM and found some corrosion on the connector pins. Using a small baby bottle nipple cleaning brush and CRC electric contact cleaner, I cleaned up the corrosion on both the pins on the PCM and the female slots on the connector. Put dialectric grease on the pins and put it back together.

I put the battery back in and the efans didn't automatically come on. Started it up and no codes (except for the stupid emissions) and it has run fine now for two days. Just like normal.

Thanks again for everyone sharing their knowledge here. I am disabled and retired, so spending a lot of money on cars is not easy anymore. You are greatly appreciated.
 

BG1988

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What is the other codes knock sensor bank 2
open circut

since some can be a secondary code

DONT" run the suv tell you get it fixed other wise more damage may happen..
 
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