I am dealing with repeated DTCs for communication failures between modules. I also have an intermittent crank, but no start issue. The schematic demonstrates that the TCM, ECM, and ignition relay all share the same ground. It’s G110. I can’t find where it is. I have limited it down to being bolted to the engine. If anyone knows where this ground is, please let me know. I appreciate any help you can provide.
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G110 is located at the right rear of the engine, mounted on the back of the cylinder head. In the diagram, it appears on a bracket just above the power steering pump pressure hose.
This is an easy connection to overlook or forget.
Before proceeding, can you take five minutes to do this six-step test first?
When testing G110, do you have a set of back probes?G110 connects to:- The black-and-white striped wire on the AC clutch- The black and white wire on the MAF air intake sensor (cavity C)- ECM connector X2 (cavities 1, 2, and 4), which also has a black and white striped wire- Automatic transmission connector X1 (cavities 1 and 18)- Brake booster pump motor (cavity 2). This can be a significant issue on the ground system because of high amperage, which often leads to burned connectors- Underwood fuse block connector X3 (cavity 45)You can easily check this by removing the rear window defogger relay. Use a test probe without spreading the pins at cavity 85, and you can do this while the engine is running. This will be similar to a voltage drop test as outlined in steps 3 and 4. The circuit inside the fuse block connects to the rear window defogger relay coil (pin 85)- Starter relay coil (pin 85)- Stop lamp relay coil (pin 85)- And backup lamp relay coil (pin 86)Please remember to mark your relays before removing them. Why are we going through all this testing in the underhood fuse block? Due to GM’s modular designs, many circuits are left with undersized terminals, such as the radiator fan power circuit in the 2008 Malibu.
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Thank you. I do have a set of backprobes. I will follow the procedure you provided. Thank you
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i will be around…
check your chat… i linked the images you will start with…