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2009 z06 that had some water damage. Water just exceeded rocker panels and since then have noticed sporadic parasitic draw. Have replaced the entire BCM without success and even after that started pulling fuses while connected to draw meter etc. Believe I’ve isolated the issue to fuse 56 in the engine compartment which is ECM/TCM/easy key. Draw was reading about 1.0 amp then went down after pulling that fuse and stayed down around 0.1. Anyone have any suggestions on what to check now?
like I said the draw is sporadic and it seems like it’s only happening 5 times out of 10. Appreciate any feedback!
You want forum members to help diagnose electrical problems on a flood car? Probably asking a lot. Good luck.
appreciate the helpful post…
Just looking to see if anyone else has any experience chasing this specific problem and would would be willing to share easiest next steps to test and diagnose.
Look up Pine Hollow Auto Diagnostics on YouTube. He has a lot of videos on tracing parasitic draws.
thanks yes I see that. However I’ve traced mine down to a specific circuit, but looking for advice on the corvette platform what’s the next logical place to check and how I would go about doing that between the ecm/BCM/easy key.
already tested every fuse in passenger footwell including replacing the BCM without success
Does the car even run ??…pulling fuses isn’t the best way to do a parasitic draw test but since you said it’s fuse 56 and you have a Z06 I’d remove the ECM connectors and see if the draw goes away….your 100 milliamps is too high…should be about 25-30 milliamps after all the modules “go to sleep”…having a scan tool would help to see if you can even communicate with the ECM and if you can if there are any trouble codes stored in it…wished GM put these engine computers in a little better spot…even under the hood is better than 12 inches off the ground…with your flooding expect electrical issues down the road.
Does the car even run ??…pulling fuses isn’t the best way to do a parasitic draw test but since you said it’s fuse 56 and you have a Z06 I’d remove the ECM connectors and see if the draw goes away….your 100 milliamps is too high…should be about 25-30 milliamps after all the modules “go to sleep”…having a scan tool would help to see if you can even communicate with the ECM and if you can if there are any trouble codes stored in it…wished GM put these engine computers in a little better spot…even under the hood is better than 12 inches off the ground…with your flooding expect electrical issues down the road.
thank you this is super helpful. Car runs great and has for years minus this draw problem and some motor issues I had due to aftermarket valve failure.
I have a Tech II vxnano and have checked for codes but haven’t seen any stand out. Hoping unplugging ECM will stop the draw and that I can simply buy a replacement to finally solve this issue!
thank you this is super helpful. Car runs great and has for years minus this draw problem and some motor issues I had due to aftermarket valve failure.
I have a Tech II vxnano and have checked for codes but haven’t seen any stand out. Hoping unplugging ECM will stop the draw and that I can simply buy a replacement to finally solve this issue!
Well if you find some water intrusion at the connectors and after making a visual inspection you can try spraying something like DeOxit into the connector and seeing if the draw MIGHT go away…those “green crusties” or vertigris as it’s technically called can be conductive under certain conditions and cause a short circuit…if not it looks like an Engine Computer is in your future.
Well if you find some water intrusion at the connectors and after making a visual inspection you can try spraying something like DeOxit into the connector and seeing if the draw MIGHT go away…those “green crusties” or vertigris as it’s technically called can be conductive under certain conditions and cause a short circuit…if not it looks like an Engine Computer is in your future.
I didn’t realize the ECM for the z06 was located much higher than a base c6. Water didn’t make it up that far anywhere close.
Question, once I can get the draw to occur, is there anything I can do with the tech ii emulator to search and see if I can pinpoint what may be the culprit?
I would still remove the connectors and check...don't think the Tech 2 can help with pinpointing the draw...remove the ECM connectors and see if the draw goes away...you can't assume anything.
I just solved a draw on this circuit two weeks ago, that had me baffled for over a year. I replaced the relays on the back of the BCM because while i had everything apart cleaning it, my dog stole them and chewed them.
Since that happened, I threw a brand new fuse in every slot. Between the two of those things, it fixed my draw on the BCM.
Yep, could be a module the problem, or could be the module not getting the BCM signal to go into sleep mode isntead.
Hell, with a flood car, problem could be corrosion on the wires under their shielding between the wire and its pin in the connector the problem at hand as well.
Here are the diagrams for the gm main lan loop to the major modules on the tan/tan BLK wires,
While here is the data 2 wires that the main modules communicate to the minor modules.
spice block 208 is to the left of the Bose amp location in the passengers foot well, and splice block is to the left of the dash cluster in the dash.
Also keep in mind that you have ground splice blocks, which could be a problem too if water damaged.
On the ground points, better to check the modules in run mode/motor off, since your dealing with lower voltage of just the battery alone, to check the modules differential readings from the BCM, since if a grounding problem more likely to rear its head with the lower voltage getting to them off the BCM when the motor is shut off, alternator not sending out 14.7 volts to the BCM.
I just solved a draw on this circuit two weeks ago, that had me baffled for over a year. I replaced the relays on the back of the BCM because while i had everything apart cleaning it, my dog stole them and chewed them.
Since that happened, I threw a brand new fuse in every slot. Between the two of those things, it fixed my draw on the BCM.
appreciate the feedback but I’m almost certain mine isn’t BCM related as I both replaced the entire thing with a brand new one AND pulled every fuse in it while the draw was present and it still remained.
05-25-2023, 05:49 PM
Help with parasitic draw
