revive2alive

What does this BCM code mean?

"DDM Messages Not Received"

revive2alive

Bought this vehicle in late March as a project. has bad engine and was left sitting for over ayear with the battery in it.
I used Snap-On Solus Pro Scan tool to get Diagnostic trouble Codes (DTC's) from the computer
I got
Engine:
P0161 2/2 O2 Sensor Heater Failure
ABS
11 LF Speed Sensor Signal Failure
13 RF Speed Sensor Signal Failure
15 LR Speed Sensor Signal Failure
24 System Under Voltage
Body
DDM Messages Not Received

I erase all these codes and turned the system off then on again. Only code remaining was the BCM code DDM Messages Not Received.
DDM is an IBM message protocol dealing with databases. I bet this is a BUS message about the battery dying but am unsure.

dave1123

No, it's okay. The message shows the Body Control Module isn't communicating with the Powertrain Control Module and it could simply be a bad connection on the data bus. Since 99 all the modules are connected to a digital data buss and constantly communicate with each other. The PCM uses the ABS wheel sensors and the transmission output shaft sensor to calculate vehicle speed. You'll also find everything displayed on the gauge cluster comes from the PCM and not from the sensors themselves.

In order to fully understand the system, you're going to need a copy of the Factory Service Manual that's available as a pdf download from pacificcoastmanuals.com that they have to call the "Full Service Manual" for copywrite reasons. It's 93mbs of compressed pdf files containing information, system explanations, component locations, diagnostic procedures, wiring diagrams, EVERYTHING you need to know about your particular jeep! It's $7.99 and about the best reference there is.

revive2alive

Thanks for the info. I'm also having a driver rear door window regulator issue that may be coming from the BCM. The rear window regulator only moves the window up. I checked the window switch out to be okay. I checked the regulator out on another door and it moves both ways. The regulator won't go down from the front door controller or the rear window switch. Voltage at the switch only shows 1 12v hot input and a 3.6v hot (switch illumination) input. There should be 2 12V hot inputs to the switch. Is this a wiring issue or a BCM issue also?

dave1123

No, more than likely it's a broken wire the the door connector bundle where it comes from the body. I currently have problems like that with 3 of the 4 doors on my 2000 WJ. In most critical problem is if my driver's door is open, nothing works. With it closed everything is fine. Last December, my passenger's side rear window would go down, but not up. Because of the weather, I just hotwired the motor to go up, then left it disconnected. The motors are permanent magnet motors are will run in either direction. All the switch does is change polarity.