Could This Be a BCM Issue?

[Doubeleive]

did you try disconnecting the battery for a few minutes? doing that and then reconnecting it may correct the issue, the modules need a good handshake to communicate properly. If not it may be worth a shot, while the battery is disconnected re-seat all the bcm harness just for good measure.

 

[TJ Baker]

Still early here, 05:30, but up and at the manuals am I. I do love a puzzle.

Both the TPMS and the key fobs send their radio frequency signals to the Passenger Door Module, PDM. The PDM needs to send off the pertinent information to the Cluster and the BCM. There is a single tan wire from the PDM to a splice pack near the left i/p fuseblock which also has one brown wire from the Drivers Door Module (DDM), one grey wire from the Cluster, and one light green wire from the BCM.

You might be able to deduce a bad connection of this serial data bus by seeing what works and what doesn't. For example if you press the drivers door lock switch and only the front doors lock or unlock, that could indicate bad wiring from the DDM, through the splice pack to the BCM.

If pressing the DDM door lock switch locks and unlocks all doors and hatch then you know the wiring is sound from DDM through splice pack to the BCM since it is the BCM that does the locking and unlocking of the rear doors and hatch. This would possibly suggest the issue may be with the tan wire from the PDM to the splice pack.



I am suggesging this due to the fact that both the TPMS and key fob systems are inoperative and those systems both require that the serial data wiring be connected from the PDM through to the Cluster and the BCM through that splice pack.

Naturally, it could be something else entirely, but this seems to fit.

 

[George B]

Still early here, 05:30, but up and at the manuals am I. I do love a puzzle.

Both the TPMS and the key fobs send their radio frequency signals to the Passenger Door Module, PDM. The PDM needs to send off the pertinent information to the Cluster and the BCM. There is a single tan wire from the PDM to a splice pack near the left i/p fuseblock which also has one brown wire from the Drivers Door Module (DDM), one grey wire from the Cluster, and one light green wire from the BCM.

You might be able to deduce a bad connection of this serial data bus by seeing what works and what doesn't. For example if you press the drivers door lock switch and only the front doors lock or unlock, that could indicate bad wiring from the DDM, through the splice pack to the BCM.

If pressing the DDM door lock switch locks and unlocks all doors and hatch then you know the wiring is sound from DDM through splice pack to the BCM since it is the BCM that does the locking and unlocking of the rear doors and hatch. This would possibly suggest the issue may be with the tan wire from the PDM to the splice pack.



I am suggesging this due to the fact that both the TPMS and key fob systems are inoperative and those systems both require that the serial data wiring be connected from the PDM through to the Cluster and the BCM through that splice pack.

Naturally, it could be something else entirely, but this seems to fit.



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You Sir are an asset to this forum! I will never posses your level of knowledge in these matters.

 

[TJ Baker]

You Sir are an asset to this forum! I will never posses your level of knowledge in these matters.

I just have too much time on my hands!!

 

[YukonRog]

Okay, so I just checked both door functions and they work fine. A little history on this vehicle, June of 2020 it jerked my wife into oncoming traffic. I believe it was due to the Steering Position Sensor being out. It said "Service Stability". She refused to drive it until I fixed it. I pulled the ABS Fuse disabling the ABS and The Traction Control. That made it drivable. But just like old school, before we had all that ABS and Traction Control. Drove it that way for a while until I recently replaced the Steering Position Sensor. Now the only thing I can comment on is it used to beep the horn when locking it with the remote. Now it takes a second push on the button to beep. You can hear the doors lock on the 1st push I might add. Now that may be something in the programming or it may be something else, I don't know. And it's very possible all 4 wheel TPMS have died because it did sit a lot. So until I can buy a TECH II, or take it to a Dealership, or just replace all 4 TPMS' we'll just drive it the way it is and see if anything else pops up. America's Tires quoted me $250 for all 4 TPMS'. Gotta budget for something here. Kinda leary about buying them on Amazon.

 

[George B]

Okay, so I just checked both door functions and they work fine. A little history on this vehicle, June of 2020 it jerked my wife into oncoming traffic. I believe it was due to the Steering Position Sensor being out. It said "Service Stability". She refused to drive it until I fixed it. I pulled the ABS Fuse disabling the ABS and The Traction Control. That made it drivable. But just like old school, before we had all that ABS and Traction Control. Drove it that way for a while until I recently replaced the Steering Position Sensor. Now the only thing I can comment on is it used to beep the horn when locking it with the remote. Now it takes a second push on the button to beep. You can hear the doors lock on the 1st push I might add. Now that may be something in the programming or it may be something else, I don't know. And it's very possible all 4 wheel TPMS have died because it did sit a lot. So until I can buy a TECH II, or take it to a Dealership, or just replace all 4 TPMS' we'll just drive it the way it is and see if anything else pops up. America's Tires quoted me $250 for all 4 TPMS'. Gotta budget for something here. Kinda leary about buying them on Amazon.

I got delco ones on Rock auto

 

[YukonRog]

Ay Carumba! George B I replaced the fan motor resistor. Therefore I may have disturbed the wires in the loom coming from the Passenger Door under the dash!
DOUBELIEVE, I'll disconnect the battery and check all the plugs and connections. Worth a shot, right guys?

 

[TJ Baker]

Now the only thing I can comment on is it used to beep the horn when locking it with the remote. Now it takes a second push on the button to beep. You can hear the doors lock on the 1st push I might add

I thought your FOBs were not working, I must have misread that somewhere.

The horn beep is programmable in the DIC personalization settings. I can set that separately for each FOB to either sound the horn or flash the lights I think. And the first FOB press locks the doors while the second press on the FOB arms the security system.

I have one TPMS sensor with a low battery. That is why my relearn fails. Now that I know how to set them up from the phone I will never go through that relearn horsesh** again!!

No need to look at PDM wiring if the FOBs work. If they work that is proof that the serial data wiring is OK.

 

[George B]

Maybe try starting on another wheel for the programming. Might prove out the system. You don’t have one of these?

 

[ks03]

Okay, so I just checked both door functions and they work fine. A little history on this vehicle, June of 2020 it jerked my wife into oncoming traffic. I believe it was due to the Steering Position Sensor being out. It said "Service Stability". She refused to drive it until I fixed it. I pulled the ABS Fuse disabling the ABS and The Traction Control. That made it drivable. But just like old school, before we had all that ABS and Traction Control. Drove it that way for a while until I recently replaced the Steering Position Sensor. Now the only thing I can comment on is it used to beep the horn when locking it with the remote. Now it takes a second push on the button to beep. You can hear the doors lock on the 1st push I might add. Now that may be something in the programming or it may be something else, I don't know. And it's very possible all 4 wheel TPMS have died because it did sit a lot. So until I can buy a TECH II, or take it to a Dealership, or just replace all 4 TPMS' we'll just drive it the way it is and see if anything else pops up. America's Tires quoted me $250 for all 4 TPMS'. Gotta budget for something here. Kinda leary about buying them on Amazon.

The dealerships I’ve worked for both had a tool that could read the tpms without doing anything to the vehicle. So if you drove there you know they’d be active, and if they can’t read them, then I’d be thinking to replace them. Problem is they pretty much have to try to read it on the service drive, otherwise paying for diagnosing eats half the money of blindly replacing them