PPS and door locks

[SouthernNights]

Ok here is a weird one. I have had a problem with the doors locking on my 09 GMC all by themselves. Not all the time, just once in awhile.

The dealer said he had never heard of that and could not diagnois the problem without a mech. sitting there watching the truck and have it happen to him. (I think I got blown off here)

Bob from Bob and Patty fame suggested that my "logic lock" (some computer thing that thinks it knows when I want the doors locked) might be screwed up. Armed with this information, I brought the truck to the dealership yesterday to get this resolved. The problem is beginning to happen a little more often.

When the Service Mgr. saw the sensors on the wheels he said that is what was causing the problem. The signal transmitted from the sensor was being picked up by the receiver in the computer. According to the service mgr., the same receiver that the door locks use was picking up the signal from the sensors.

This sounds like another blow off, but not knowing car computers, thought I would see if anyone else has experienced this. Bob, what do you think.

Pat, has anyone else had this problem that you know of??

 

[Bob&Patty]

Larry, you can ask Patty if you want....but so far she can put gas in her own car. She also knows where the loud pedal is. She has 2 speeds..........stopped and pedal to the metal.

What sensors on the wheels??? The factory tire pressure moniters?? They have no bearing on the door locks since the vehicle is turned off and the wheels are not turning.

Larry, it is possible that something outside of the vehicle could be causing this to happen. Do you have any electronic equipment that might send some kind of a signal near your truck??? But, seems to me that this did not start happening until you had ONSTAR unlock your truck. Am I correct??

Did anyone at the dealer call the "GM TECH LINE" and/or do a bulletin search for this problem?? BTW, does the dealer supply you with "BS" repellant when you arrive??

 

[Boca_Shuffles]

Does this only happen when the vehicle is moving (i.e. over 10 mph) or when the vehicle is standing still and idling?

The auto lock while moving feature is something that you can enable through your setup options. You might disable this feature and see if the doors still lock themselves.

Check your owners manual to see if (how) to enable/disable this option.

 

[2010augusta]

I believe that Larry is talk about the signal coming from the Pressure Pro System (PPS) is mimicking the remote lock signal on the truck causing the doors to lock for no apparent reason.

Larry as a quick thought you might try moving the sensors on the truck to the trailer and vise-versa since it could be a sensor on the truck and making the distance further could eliminate the problem. just a thought.

 

[SouthernNights]

Sorry for not explaining throughly. It happens after I stop, engine off. Doesnt matter where the keys are.

I have not tried with out the PPS. I guess I need to remove them from the truck next.

Bob, I meant Pat McFall, not your Patty. It is interesting that the first time I brought the truck to the dealer, he said nothing could make the doors lock by themselves. After asking him about logic lock (Bob's suggestion) then all of a sudden it was the PPS doing it. And no, he did not call the Tech Line-too busy eating his biscuit and gravy.

 

[Pat McFall]

Sorry for not explaining throughly. It happens after I stop, engine off. Doesnt matter where the keys are.

I have not tried with out the PPS. I guess I need to remove them from the truck next.

Bob, I meant Pat McFall, not your Patty. It is interesting that the first time I brought the truck to the dealer, he said nothing could make the doors lock by themselves. After asking him about logic lock (Bob's suggestion) then all of a sudden it was the PPS doing it. And no, he did not call the Tech Line-too busy eating his biscuit and gravy.

Larry...........never heard of this happening to any of our customers. Do you know what frequency the door locks operate on? I will touch base with the head troubleshooter and see if he has heard of this happening. He works with a lot more PressurePro owners than I do. I'll let you know.

Pat

 

[SouthernNights]

Thanks Pat. I doubt it is the PPS but before I go back to this dealership I want to have a little more info. I find it hard to believe that PPS or any other tpms would build a unit that would could interact with the vehicles computer system.

 

[Pat McFall]

Thanks Pat. I doubt it is the PPS but before I go back to this dealership I want to have a little more info. I find it hard to believe that PPS or any other tpms would build a unit that would could interact with the vehicles computer system.

The operating frequency for the PressurePro is 433.92 MHz FM. Maybe you can check the frequency for the door locks. I really don't think the problem is with the PressurePro. I'll touch base with the PP troubleshooter later this morning.

Pat

 

[Netem]

Larry, you might want to check with another dealer. I have found that not all dealers are created equal. Maybe find one that doesn't have his mouth full of biscuits and gravy.

 

[TXBobcat]

I have had my pps since 2006 and I have had no problem with my door locks, but of course I have a FORD...

I hope you find out the problem. I would take the sensors off for a while and see if it keeps doing it and take it back to the dealer with no sensors.

Let us know how this comes out..

BC

 

[wdk450]

Electromagnetic Interference

Gang:
As a retired Certified Hospital Bomedical Equipment Technician with 30 plus years in the industry I can tell you that interference from electronic devices is an unpredictable problem. It involves the power level, frequency and type of modulation of the transmitting device, the proximity of the 2 devices, and the suseptablity of the receiving device to electromagnetic interference.
In experimental trials at our University Medical Center we were able to repeatedly make a CERTAIN make/model ventillator stop assisting patient breathing (in a test setting) when a CERTAIN make/model cell phone was in close proximity. In another test an IV pump was caused to suddenly run at full speed from a slower setting with a CERTAIN cell phone in close proximity. This could be fatal when administering certain strong drugs such as chemotherapy or blood thinner agents. There are too many electronic medical devices multiplied times too many models of cell phones (with new models coming out daily) to completely test for this. Seperating medical devices and cell phones by more than 6 feet seems to universally eliminate the problem. By the way, most people don't know THAT AS LONG AS A CELL PHONE IS TURNED ON IT IS TRANSMITTING OUT A "HERE I AM!" SIGNAL TO THE NEAREST CELL TOWER EVERY 6 SECONDS OR SO!!! This is so your phone can be located for an incoming call.
You were checking on TPS frequencies and door lock frequencies. Although this is a good place to start be aware that the interfering signal does not have to be on the same frequency as the usual received frequency. A complex waveform like a square wave (think Digital) is composed of the fundimental frequency (example 10 MegaHertz) and ALL harmonic frequencies of that frequency in decreasing power levels (example 1/2 power @ 20 Mhz, plus 1/4 power @ 30 Mhz, plus 1/8 power @ 40 Mhz, ad infinitum).
It takes a lot of engineered metal shielding, antenna and power filtering to fight these problems, and they can be very difficult to isolate.
I know this post isn't entirely applicable to getting your door locks to work, but I thought I would take this opportunity to explain EMI and make people THINK when they are in Acute Medical facilities with their cell phones on.

 

[timdebs]

Just another thought, if it were the sensors they are constantly sending info to the monitor/receiver, so why wouldn't they be locking your doors all the time?

 

[lelandpa]

Just a thought, could the body computer be going bad? It happened to me with my Impala, made the car do all kinds of goofy things. Started with the locks, then lights, radio and wipers started acting up. It did it with the car running and shut off.

 

[Bob&Patty]

Lelandpa, yes there was an issue with the BCM on certain Impala's. Yes the car would go wacko at times. I replaced lots of them for that. It did require a complete reprograming of the car to accept the new BCM. Aren't electronics just a wonderful thing.

Larry, question, why do you have PPS's on the the truck? It should have the OEM pressure sensors built in. Remember the sensors are the valve stems. Someone may have hit on a cause. To reprogram the sensors, you do have to reset each tire and the horn will honk when it resets. You are using the same module to program the tires that the door locks use. Still kinda weird. Try taking the PPS off and see what happens. Thank goodness it was the other Pat. With my Patty, if something quits working, there is no diagnoses involved, its off to the store to get a new one. Even if it just came unplugged. "IT'S DEFECTIVE...........THEY JUST CANT COME UNPLUGGED". Ya'll think I jest..............NOPE.

 

[JohnDar]

Lelandpa, yes there was an issue with the BCM on certain Impala's. Yes the car would go wacko at times. I replaced lots of them for that. It did require a complete reprograming of the car to accept the new BCM. Aren't electronics just a wonderful thing.

Larry, question, why do you have PPS's on the the truck? It should have the OEM pressure sensors built in. Remember the sensors are the valve stems. Someone may have hit on a cause. To reprogram the sensors, you do have to reset each tire and the horn will honk when it resets. You are using the same module to program the tires that the door locks use. Still kinda weird. Try taking the PPS off and see what happens. Thank goodness it was the other Pat. With my Patty, if something quits working, there is no diagnoses involved, its off to the store to get a new one. Even if it just came unplugged. "IT'S DEFECTIVE...........THEY JUST CANT COME UNPLUGGED". Ya'll think I jest..............NOPE.

If he's got a GMC 3500 Dually, it does not come with OEM TPMS. I thought mine did until I learned otherwise. I was told it is only put on the SRW trucks.

On the "fun with electronics," I found that my remote door opener would set of somebody else's car alarm a while ago in a grocery store parking lot. Hit it once, their lights and horn went ballistic. Hit again, it shut off. Was fun (they were'nt there). I THINK I shut it off before I drove off.

 

[SouthernNights]

All good info guys, especially the medical equipment. Never knew any of that.

Bob, I am using PPS on my truck because the GM does not give you psi. It will tell you if the tire is low but thats it-but then you knew that. I am to much of an info junkie to just have a warning - I want specifics too.

Tim, you would think but if out 5 million things made and only one can go bad-well guess which one I have.

BTW- where have all the other posts under the TPMS sub forum? I thought there was alot of threads here for info.

P.S. John-so YOUR the one.

 

[Bob&Patty]

Larry, your right, forgot the trucks only warn you. Used to seeing the pressures in numbers on Cads and Vettes. If I remember I will ask again if anyone in the shop has seen this before. Bob

 

[htneighbors]

Just a thought, could the body computer be going bad? It happened to me with my Impala, made the car do all kinds of goofy things. Started with the locks, then lights, radio and wipers started acting up. It did it with the car running and shut off.

Stephen King oughta write a book...

 

[boatto5er]

Let's not forget to factor in Larry's "MAGNETIC" personality!

 

[leftyf]

All good info guys, especially the medical equipment. Never knew any of that.

My 2008 Silverado tells me exactly what the PSI is in each tire.

I think that one of your neighbors has a fob that has the same digital signal of yours.