nomographer
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I'll share in case someone has an alternative idea about what happened here.
Died with no real warning. Sure enough I left from an errand and ESS stopped the engine at a light, but I thought I had turned it off. A few minutes later at a long light I purposefully let it stop. Light heat load, radio only. On engine restart i saw something about the forward camera needing cleaned, a quick start/stop message, and then it was clear. Sadly after crossing the next intersection up popped the dreaded "Stop safely, vehicle will shut down soon", so I stopped on an entrance ramp.
I tried restarting everything twice, several minutes apart, but it would only display 11.8V, quickly drop to 11.4V, and then the message blocked everything. Tow driver couldn't get it started.
Likely unsurprising: Both batteries DOA, replaced, p2504 charging system output high, p2af5 starter relay 3 stuck on, diagnostic found fuse array 125 amp fuse blown.
Driving a few days later I saw 14V on the outbound trip, but mostly 12.6 with a few slides up to 14V or 13.6V. This reminded me that I hadn't seen 13.0V on the voltmeter while driving for a long time.
My conclusion: One battery was dead, parasitic but not enough to draw down ignition, but then it internally shorted on the ESS restart, charging system raced blowing the fuse, and it couldn't maintain above 11.4V since one of them was drawing down the other.
Q: Why would the 125A blow? That seems to be the steering system. (I didn't test it, so it may be misreported)
Q: If they put in the wrong array, 53AA, but I have the tow package (54AA), what's gonna fail? Presumably a 100A fan would blow it just starting. Does that 60A/100A handle other things? IE if I turn on my big lights, aux switches, will it kill the 60A? (Sorry I haven't had a chance to look at the circuit diagrams just yet)
Q: What other failure explanations am I missing for this event?
I still need to order a spare array, and have caught up on the fuse 42 trick, but my worry is being unable to field repair this since there was no low battery, ESS protection, or any other warning. I'll probably put full battery checks on annual maintenance.
Thanks for listening!
Died with no real warning. Sure enough I left from an errand and ESS stopped the engine at a light, but I thought I had turned it off. A few minutes later at a long light I purposefully let it stop. Light heat load, radio only. On engine restart i saw something about the forward camera needing cleaned, a quick start/stop message, and then it was clear. Sadly after crossing the next intersection up popped the dreaded "Stop safely, vehicle will shut down soon", so I stopped on an entrance ramp.
I tried restarting everything twice, several minutes apart, but it would only display 11.8V, quickly drop to 11.4V, and then the message blocked everything. Tow driver couldn't get it started.
Likely unsurprising: Both batteries DOA, replaced, p2504 charging system output high, p2af5 starter relay 3 stuck on, diagnostic found fuse array 125 amp fuse blown.
Driving a few days later I saw 14V on the outbound trip, but mostly 12.6 with a few slides up to 14V or 13.6V. This reminded me that I hadn't seen 13.0V on the voltmeter while driving for a long time.
My conclusion: One battery was dead, parasitic but not enough to draw down ignition, but then it internally shorted on the ESS restart, charging system raced blowing the fuse, and it couldn't maintain above 11.4V since one of them was drawing down the other.
Q: Why would the 125A blow? That seems to be the steering system. (I didn't test it, so it may be misreported)
Q: If they put in the wrong array, 53AA, but I have the tow package (54AA), what's gonna fail? Presumably a 100A fan would blow it just starting. Does that 60A/100A handle other things? IE if I turn on my big lights, aux switches, will it kill the 60A? (Sorry I haven't had a chance to look at the circuit diagrams just yet)
Q: What other failure explanations am I missing for this event?
I still need to order a spare array, and have caught up on the fuse 42 trick, but my worry is being unable to field repair this since there was no low battery, ESS protection, or any other warning. I'll probably put full battery checks on annual maintenance.
Thanks for listening!
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