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There is another module that can affect both doors at the same time and that is the Keyless Entry Module. If you can get access to a scanner that can read body codes you need to be looking for some B DTCs such as B1474, B3849, B2494, B250B, B251A-B251F, B252A, B252B, B297B or B297C, B3125, B3130, B3135, B3140, B3145, B3150, B3155, B3797. There are a lot of things involved in the door lock circuits and you really need to know the codes involved so you know where to start looking. There are over 50 pages in the FSM that address door lock issues so it helps to narrow down the search ahead of time by knowing the codes.
I will try and post some pictures of the schematics and block diagram so you can get an idea of what is going on. If you can find the GM RPO sticker on the car see if you have AF8. There is a deadbolt function that will dead lock the interior door switches so they will not operate but the manual doesn't say whether or not that will keep the exterior switches from operating.
Bill
Last edited by Bill Dearborn; 07-16-2017 at 04:52 PM.
Does the second fob behave the same way? The fact that the fob only works when it is in the steering column leads me to believe you may have an issue with communications from the fob itself.
There is another module that can affect both doors at the same time and that is the Keyless Entry Module. If you can get access to a scanner that can read body codes you need to be looking for some B DTCs such as B1474, B3849, B2494, B250B, B251A-B251F, B252A, B252B, B297B or B297C, B3125, B3130, B3135, B3140, B3145, B3150, B3155, B3797. There are a lot of things involved in the door lock circuits and you really need to know the codes involved so you know where to start looking. There are over 50 pages in the FSM that address door lock issues so it helps to narrow down the search ahead of time by knowing the codes.
I will try and post some pictures of the schematics and block diagram so you can get an idea of what is going on. If you can find the GM RPO sticker on the car see if you have AF8. There is a deadbolt function that will dead lock the interior door switches so they will not operate but the manual doesn't say whether or not that will keep the exterior switches from operating.
Bill
Thanks Bill! The only B DTC I get is B0100 which I believe is related to the airbag recall I haven't taken care of yet. AF8 is not listed on the RPO sticker.
Looking at the fuse box in the rear today I noticed R5 is for THEFT (DOOR LOCK SECURITY). Was only looking at fuses the first time around. It is a unique part # to the other relays on the car so I couldn't just swap it with another to see if that solved the problem. When I get more time I'll give it some power and test resistance when charged up.
Does the second fob behave the same way? The fact that the fob only works when it is in the steering column leads me to believe you may have an issue with communications from the fob itself.
Both fobs behave the same. I did replace the keyless entry antenna ($13) that is located under the carpet between the seats today but that did not help.
Here are the main schematics and theory of operation for the door locks.
Bill
Looking at this diagram I am thinking the Keyless Entry Control Module is to blame. The door locks themselves work. The lock/unlock indicator lights work. It's just that the handle switches seem not to be communicating to the latches.
Also, noticed this weekend that the hatch button is acting a little weird. The button works when the car is unlocked but does not work when the car is locked. Again, this leads me to believe the Keyless Entry Control Module may be to blame.
Looking at this diagram I am thinking the Keyless Entry Control Module is to blame. The door locks themselves work. The lock/unlock indicator lights work. It's just that the handle switches seem not to be communicating to the latches.
Also, noticed this weekend that the hatch button is acting a little weird. The button works when the car is unlocked but does not work when the car is locked. Again, this leads me to believe the Keyless Entry Control Module may be to blame.
I think that is the way the hatch button is supposed to work.
On my other cars, you can open the trunk without a key if the car is unlocked, but not if it is locked.
07-16-2017, 04:49 PM
