My 2012 Yukon Denali Hybrid did one of those out of nowhere brake lock ups on its own while doing 50mph. Gave me a good neck snap. It was a quick but hard pulse and release of the brakes followed by all the error messages to basically check every system. It went into limp mode. After turning it of an on and letting it rest, nothing changed. I limped it home. Put a scanner on it and not surprisingly there was a loss of communication with most systems. After I deleted the codes it did not want to start but after several turns of the key it started and stalled a few time and now remains running. So I need to figure out the likely culprit causing all the communication issue.
Codes were as follows:
U0073-Can Bus Communication DTC Severity,
P0700-Trans Control Module requested MIL Illumination,
P0AC4-Hybrid Powertrain Control Module requested MIL Illumination,
U0100-Lost communication with Engine Control Module,
U0101-Lost Communication with Trans Control Module,
U1888- Hybrid Power Control Module lost communication with Battery Energy Control Module,
U1885- Battery Engine Control Module lost communication with Hybrid Powertrain Control Module…
The strangest thing of all to me a non mechanic is that if I start it now at idle it has a very audible chattering/clinking noise from underneath the truck. I will upload a video so you can hear it.
The truck has had a service suspension system message for 2 years. I had the self leveling shocks checked at a mechanic for leaks and they mechanically all checked out with no leak so the thought was that it’s a bad sensor or control module. It still works and the shocks hold air so I have just ignore it. It does like to cycle on and off very often without any real load changes or weight of the vehicle so it may be burning out? I’ve read about the Active Suspension Control Module rusting out or catching fire due to shorts and that being the cause of many other communication errors as it send a voltage issue signal that shuts everything else down momentarily.
With regards to a loss of voltage message , this also has happened twice before about a year apart over the last 2 years where while driving on the highway on a long road trip, when I went to brake the braking system power assist shut down due to a voltage drop or variance detected causing us to lose all power to the brakes and having to stomp the pedal to the floor and stand on it to bring it to a stop eventually. Picture manual brakes with no power assisting.
The fact that it has lost the brakes twice in the past and now locked up the brakes all due to a communication loss or voltage variance I need to find out where that is originating from. Which module is shot. It seems it would be in the Active Suspension Control Module and it maybe the SELF leveling Sensors due to the 2 year history of the constant cycling issue but… why would that now cause the truck to idle and have this audible chatter that seems transmission related?? I need guidance, help and would love a Northern New Jersey, Sussex County mechanic recommendation otherwise it’s the dealer.
PS I am having issues posting the video
Codes were as follows:
U0073-Can Bus Communication DTC Severity,
P0700-Trans Control Module requested MIL Illumination,
P0AC4-Hybrid Powertrain Control Module requested MIL Illumination,
U0100-Lost communication with Engine Control Module,
U0101-Lost Communication with Trans Control Module,
U1888- Hybrid Power Control Module lost communication with Battery Energy Control Module,
U1885- Battery Engine Control Module lost communication with Hybrid Powertrain Control Module…
The strangest thing of all to me a non mechanic is that if I start it now at idle it has a very audible chattering/clinking noise from underneath the truck. I will upload a video so you can hear it.
The truck has had a service suspension system message for 2 years. I had the self leveling shocks checked at a mechanic for leaks and they mechanically all checked out with no leak so the thought was that it’s a bad sensor or control module. It still works and the shocks hold air so I have just ignore it. It does like to cycle on and off very often without any real load changes or weight of the vehicle so it may be burning out? I’ve read about the Active Suspension Control Module rusting out or catching fire due to shorts and that being the cause of many other communication errors as it send a voltage issue signal that shuts everything else down momentarily.
With regards to a loss of voltage message , this also has happened twice before about a year apart over the last 2 years where while driving on the highway on a long road trip, when I went to brake the braking system power assist shut down due to a voltage drop or variance detected causing us to lose all power to the brakes and having to stomp the pedal to the floor and stand on it to bring it to a stop eventually. Picture manual brakes with no power assisting.
The fact that it has lost the brakes twice in the past and now locked up the brakes all due to a communication loss or voltage variance I need to find out where that is originating from. Which module is shot. It seems it would be in the Active Suspension Control Module and it maybe the SELF leveling Sensors due to the 2 year history of the constant cycling issue but… why would that now cause the truck to idle and have this audible chatter that seems transmission related?? I need guidance, help and would love a Northern New Jersey, Sussex County mechanic recommendation otherwise it’s the dealer.
PS I am having issues posting the video
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