2006 avalanche check engine light

One of our other installers put a Avital 4000XL Remote Start Keyless Entry into a 2006 Chevrolet Avalanche about a month ago.  The customer came back today and said that it needed to be fixed because his check engine light came on and the dealer reset it but told him it was caused by the remote start because it was connect to an oxygen sensor wire.  The check engine light is no longer on and i have tried to figure out what if anything we did could have caused it to come on.  I know not powering the second ignition would cause it not to come on but i tested that with a DMM and it is working fine.  The only thing we put in this car is the Avital and a 457GW.  Does anyone have any ideas of what could be causing this or if it is even something we did?  I tested every wire and everything seems to be functioning as normal and I remoted started it, used valet takeover, locked and unlocked it, let it run and i cannot get the check engine light to come, so I am thinking it was nothing to do with the remote start just the dealership blaming aftermarket parts for their issues.  Thanks for taking the time to read this long post and thank you for any help.

Well if the customer no longer has a CEL and the remote start is being used, figure out the equation....If the remote start was the problem the CEL would be coming back on when using the remote start...I would call the dealership and ask them what the problem was and how that is related to the remote start...I always tell the customers that the dealership will try and blame problems on anything else but the car...

The dealer is pretty stupid, unless your tach wire is wrong. The O2 wiring only goes to the engine computer. If you have no connections outside of the car then tell the customer that the dealer probably lied to him.Certified Security Specialist

Always check info with a digital multimeter.

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this may not be nearly the case but I throw it out there just in case. Was a data interface installed? the reason I ask is my factory battery took a crap 1 year into owning an avlanche. The dealership blamed the alarms current draw. they even gave the numbers. i tested myself and didnt get the same numbers. anyways, the tech pulled power and blanked out my datainterface. I opened the door to check something while leaving the dealership and got a airbag system failure light. The datalink box was tx'ing the wrong data and confused the computer... Sorry that was long winded...Good luck..

I had the same thing from a dealership a couple of weeks ago. The dealership told me that there was a tech bulletin out that said that remote starts and alarms were causing the problem so I had him fax it over to me. Upon reading it it states that if there is an ignition kill with a mechanical relay interrupting one of the ignition wires that while driving down the road that the relay could chatter causing the ignition to power off and on which could cause unburnt fuel to go into the catalytic converters and cause catalytic converter failure. The big problem is that most dealer techs dont actually read the tech bulletins fully. That is what happened in my case. I called the service manager and explained his tech bulletin to him and he was very nice and apologized to me for any inconvenience his tech may have caused. I kept the fax that he sent me. If you would like a copy of it pm me with a fax number and I will get one over to you.