Recently purchased a 2009 Escalade Hybrid. I already knew it had problems, but I figured I would take my chances. From the start I knew it had the messages on the dash to service

Power Steering

Stability System

Traction Control

4x4 Wheel

Right before I purchased, I took it to Auto Zone and had them hook it up. Basically 02 sensor and it did say hybrid battery exceeded.
I did a lot of research after purchase and checked all fuses. Everything was good. Although I thought it was funny 2 things for the fuel pump is missing? I am stating to think it doesn’t have one? Anyways I did not check all the relays except the pcm which I swapped another one for a minute that I knew wouldn’t matter. I started messing around with the harnesses to make sure they were all plugged in. After tightening them all the codes went away. It is also making some kind of rattling sound from underneath it when I first start it, idling and take off. I thought it could be and EGR valve since I started taking off the manifold and clean it and the next day it was running great with no codes or noise. So I purchased one and went to a shop and they told me I don’t have one? I am normally able to look up stuff and kind of solve but there is not much info, pics, posts, ect… about Escalade Hybrids. So I am reaching out on here because I do not have money to take it to the dealership at full price. I love the post about getting the Bluetooth OBD to get the readings on voltage to see if the hybrid battery is the problem. It will not pick up the readings on Torque Pro. Also on my NAV screen it will not showing any levels or what I’m mode I am driving in. In the one post I seen It should light up in green. Another clue besides that not working, my power tilt wheel is stuck up, the adjustable brake and gas pedal not working. Is this all linked together? So you know when I use my scan tool it will not give anything just stuck saying reading. I have to play with the 3 harnesses to get the actual real. The bluetooth OBD today did the same thing but I seen the light they have on it. So it did have power but no communication. Which I am now only getting code U0100. Everytime I move the wires I get all kinds of different codes. I don’t know what is real anymore. Yesterday I was drivind just fine and it said on the dash “Engine Power Ruduced”. Gears not shifting when accelerating. The other day it stalled out after stopping and had to wait for battery to charge. Mechanics are afraid to touch it. I have narrowed it down to about 5 things. One of the I have more questions about hybrid battery charging which I will post another thread. Anyone familiar with these problems please help. Oh, I can also post the results from Torque Pro.
Codes
​​​Fault log report generated by Torque for Android=========================================== ======

Vehicle VIN:
Vehicle Manufacturer:
Vehicle Calibration ID:

Current Fault Log
------------------
P061B: Unknown code - More information may be available on the web
P0A80: Unknown code - More information may be available on the web
U0100: Unknown code - More information may be available on the web
U1876: Unknown code - More information may be available on the web
U1879: Unknown code - More information may be available on the web
U1886: Unknown code - More information may be available on the web

Pending Fault Log
------------------
P069E: Unknown code - More information may be available on the web
P0700: Transmission Control System (MIL Request)
P0AC4: Unknown code - More information may be available on the web
P2271: O2 Sensor Signal Stuck Rich bank1 Sensor2

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

End of report.

 

Love Torque, but it's probably not pulling all the codes. You need a professional tool.

 

I happen to come across a service bulletin about problems and solutions for different GM models. The 09 was specific about a short or onep circuit in the data link or GMLAM. There everything that has the communication cation problem is all on that same circuit. So I did narrow that down. I down know what procedures to test the curcuit, pins, wires. I'm also afraid of getting shocked by that 300 bolt battery in the back. I'm I able to test wires with the battery hooked up. I bought a multimeter because I'm dying to see if the individual cell modules are out of balance. Thinking maybe that has something to do with it. Besides not knowing the safe procedures to do this test I'm not sure where this resistor is, or the GMLAN, and which set of wires it is. I went to buy them all and go to a mechanic and give it to to do but nothing came up for mine. Can't wait to see if this will stop that rattling ruckus noise when I first start the car and drink sometimes. If that is not the problem then I know the hybrid battery is bad if it is not the catalytic converter.

 

I have attached a GM Two Mode hybrid diagnostic chart with code descriptions that helped me through some issues with my 2009 Tahoe. Hope that helps. Note: You may need to invest in a Tech2 to truly be successful, since the vehicle has so many issues.

 

He needs to check if the pins on the transmission harness backed out esp since it has a transmission code sorry i don't have that TSB on the computer i'm using

 

how did you manage to sort it out after all