Vehicle towed in w/ dead battery. Battery voltage at 3V. Charged and now battery tests ok, but when running voltage at battery never increased.

Stored all modules codes then cleared to have reoccuring P0621:00 Generator L-terminal circuit code.

Performed flowchart per code and was suggested to test or replace alternator, which I chose to replace. Dealer part-very expensive, but once replaced found 14.4V at battery. Fixed but me being me I went further.......

Per flow chart, stage 3, I found 3.2V at connector disconnected from alt. with KOEO. Specs is 3-5V so I replaced the alternator but was a bit worried that it was at the lower end of specs.

I scoped the L terminal, again w/ KOEO and am puzzled by what I see. Instead of being a clean square wave, the lower trailing edge is rounded. [BATT/Charging/Starting Photo]

Tried different terminals. Even used a different scope. Still got the same signature.

Anybody see this before? Been waiting for a test vehicle to come in, but still waiting. Figured I'd hit you guys up for thoughts.

Thanks

James George
Owner
Eve's Automotive
West Sacramento, California, USA

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