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Keyless Entry not working...BCM?

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9K views 20 replies 8 participants last post by  654L80 
#1 · (Edited by Moderator)
Hello all,
I am new to the fourm! I bought a new to me 2008 Gmc 2500 Duramax about a week ago. Truck was very well taken care of. I noticed driving to work the other day my low tire light came on said pressure was low then went out and came back later on with a constant flashing tire indicator and error message saying "service tire monitor system" along with that my keyless entry no longer works remote start etc. I know its not the battery in the remote its been replaced. Any ideas. Could it be a bad BCM?
 
#2 ·
Welcome to DieselPlace
I moved your post over to "Electrical" for better views and responses

:thumb:
 
#3 · (Edited)
It could be lots of things. First start by having your truck scanned with a scanner that will read the BCM. The national autoparts chain stores (Autozone, etc) usually have such scanners. There may/may not be codes, but if there is, that's at least a better place to start than guessing. Write down all the codes and report back. Make sure your battery is fully charged and the battery connections are clean on both ends. Amazing how many problems occur because of bad battery.
 
#4 ·
Sounds more like an RCDLR issue.
 
#9 ·
I'll have to admit that the RCDLR stumped me. Had no idea what that meant.

Remote Control Door Lock Receiver Programming and Setup

Important:


  • When replacing the remote control door lock receiver (RCDLR), the tire pressure monitoring (TPM) information can be learned to the new RCDLR in one of two ways. These two methods are reflected in the selections below. Only choose one of the methods; it is not required to do both methods when replacing the RCDLR.
  • If you choose to perform the Copy and Paste TPM Information procedure, Step 1 must be performed BEFORE removing the old RCDLR. This procedure requires that specific TPM information be extracted from the old RCDLR prior to its removal.
Remote Control Door Lock Receiver Replacement - Copy and Paste TPM Information

This procedure will learn the TPM information to the new RCDLR using the Copy and Paste function on the scan tool. This procedure will extract the TPM Tire Type information as well as the sensor data from the existing RCDLR prior to its replacement and store this information in the scan tool. After RCDLR replacement and SPS programming, the tire type and sensor data stored in the scan tool is written to the new RCDLR, negating the need to perform the tire type setup and sensor learn procedure.

This procedure should be considered as the first programming choice when replacing an RCDLR. The Copy and Paste procedure eliminates the possibility of incorrectly inputting the tire type or learning stray TPM sensors.

Important: This step must be performed prior to the removal or replacement of the old RCDLR.



  1. Using a scan tool, navigate to the Copy and Paste TPM Information procedure and copy the existing TPM information from the RCDLR using the outline below. Follow the on-screen instructions after selecting Step 1:

    • Vehicle Control Systems
    • Module Setup
    • Remote Control Door Lock Receiver
    • Copy and Paste TPM Information
    • Step 1

  1. At this point, install the new RCDLR.
  2. Program the RCDLR - Refer to Service Programming System (SPS). See: Testing and Inspection\Programming and Relearning
  3. Using a scan tool, navigate to the Copy and Paste TPM Information procedure to paste the stored TPM information using the outline below. Follow the on-screen instructions after selecting Step 2:

    • Vehicle Control Systems
    • Module Setup
    • Remote Control Door Lock Receiver
    • Copy and Paste TPM Information
    • Step 2

  1. Program the keyless entry transmitters - Refer to Transmitter Programming. See: Testing and Inspection\Programming and Relearning
Remote Control Door Lock Receiver Replacement - TPM Sensor Learn

This procedure will learn TPM information to the new RCDLR by manually inputting the tire type using the scan tool and performing the TPM sensor learn. This procedure should be performed if the above Copy and Paste procedure can not be completed. An example of this would be an RCDLR that is unable to communicate with the scan tool and is required to be replaced.



  1. RCDLR Programming-Refer to Service Programming System (SPS). See: Testing and Inspection\Programming and Relearning
  2. Keyless Entry Transmitter Programming-Refer to Transmitter Programming. See: Testing and Inspection\Programming and Relearning
  3. Tire Type Setup:

  1. Install a scan tool.
  2. Select Remote Control Door Lock Receiver under Module Setup in the Vehicle Control System menu.
  3. Select Tire Type/Pressure Selection.
  4. Follow the on-screen instructions.

  1. Tire Pressure Monitoring Sensor Learn-Refer to Tire Pressure Sensor Learn.
 
#6 ·
It sounds like a TPM sensor. With your truck being a 2008 the batteries in your sensors are now 10+ years old. Find a tire shop that can read each individual sensor and tell you which one is dead and replace that sensor. Chances are you're going to have to change all of them eventually.
 
#7 ·
Doesn't explain the key fob not working ;)
 
#11 ·
D you understand what the DTC codes mean that were found on your truck?? Did you look up the those codes on this forum or on the internet generally?
 
#13 · (Edited)
So now you know that at some point there was a communications problem within the truck, and that the TPMS gave you a message and your keyless entry/remote start does not work. It certainly sounds like the RCDLR could be the problem, but it might be the circuit that is faulty, it is not communicating with the rest of your car's computers. At a minimum, I would check to make sure the module has power and grounds. The red and white wire on the connector is the B+, the black and white on the other end of the connector is the ground, and the dark green wire is the serial data communications link.

As you can see, the RCDLR (cost about $100) will also take some programming, if you decide to replace that.

Does the truck have aftermarket radio, anything else aftermarket, metalized window tint? Anything that could produce RFI that could interfere with the RCDLR performance.
 
#17 ·
Ideally you want to know what is causing the communication lines problems, and be able to prove a fix, before deciding what parts to replace, if any. I don't know how a person can do that easily when you have potentially multiple DTC problems being logged, and actual operational problems, at least not without some rather expensive tools.

I think I would start by disconnecting the RCDLF, then clearing all codes in the computer, then seeing what codes come back if any. Drive it for a few days and then re-read for codes. You can live with out the remote features for a few days. It could be that the RCDLF is the cause of all the communication problems, and that the removal of the RCDLF eliminates those problems. If so, the solution is pretty clear, replace and reprogram the RCDLF.

On the other hand, it could be that something else in the truck is causing the problems to the RCDLF, the opposite of what is outlined above. It could be that the BCM is the problem, or some other device. That might be harder to find. If a person had an automotive oscilloscope, the job would be much easier, but few home mechanics have one. I don't. I suspect you don't either.

A competent diagnostician could provide the accurate diagnosis and maybe even replace the bad part for you. Maybe at your local dealership, but maybe not.

In one of the posts Brandon, you said your truck was stock except that the DPF has been removed. When DPF removed, the tuning must be changed to accommodate this removal, and a 'tune ' is applied to the ECM. So you truck is tuned in some manner. Most people would have had some HP added with the tune, maybe other changes also. If you know who the previous owner is, they may be willing to tell you about the tuning.
 
#18 ·
First off thank you Ron for your prompt and thorough responses. I will try unplugging the module and see what happens re-read codes and hopefully that will steer me right. Like you said without a better scanner to tell us much its tough. Im trying to stay out of the dealership as much as possible. Would you happen to kmow the location of the radio remote? Is it the module that backs the BCM?
 
#20 ·
Truck is old enough...I’d start simple and cheap.

Inspect, clean, repair or replace as needed ALL grounds.

Clear codes, then start diagnosing repairs if things are still whacked.
 
#21 ·
Also check alternator. A bad diode etc. will cause modules to act up
 
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