Hello members. I have a 2007 GS350 AWD with 230,000 km on the odometer. Yesterday morning I noticed my battery light was on so I left the car at home. After work I had some time to run some tests and found the below readings.
1. Engine off - Voltage across the battery terminals = 12.52V
2. Engine on @ 1500 RPM with no load = 12.94 V
3. Engine on @ 1500 RPM with loads (full headlights, rear defroster, radio, AC) = 11.86 V

After about 5 minutes I noticed some smoke coming up from underneath the engine on the driver's side (first picture), but was not able to locate the source. When I turn off the engine I notice the smoke was coming from the alternator (second picture). I guess with the engine on the fan was blowing the smoke back towards the engine.

This morning I needed to get something from my car but the remote could not open the door. I went to measure the voltage on the battery and it was reading zero. I took the battery out and did a continuity test across the positive and negative battery cables on the car and it was showing a short!

I know definitely I will need an alternator, but why is it showing a short? Could this have caused some damage to things like ECU? The Lexus battery is less than a year old (installed on Nov., 2016), can I just re-charge this battery or do I need a new one?

Appreciate any feedbacks

 

The alternator may be bad and showing up as a short in the electrical system. I think under load/no load with the engine running, it should read anywhere in between 13V to 14.7V.

 

13.7-14.0 should be your operating voltages if no heavy load (like an audio system).

If it's ICE COLD, it should read 14.2, I've yet to see 14.7 (I have a digital voltmeter straight into the battery and secondary voltmeter telling me my voltage levels on my amplifier).

(For future reference)

P.S. Replace alternator, and quite possibly battery, if you're not using a AGM battery, and it is a wet cell, most likely that battery's gone.

 

So I left my less than 1 yr old Lexus battery on the charger at 4 A rate for about 16 hours total and then let it to settle overnight and the reading was 13.2V (battery not hook up to the car). Today (Sat 12-Aug-2017) I got the alternator replaced and have my mechanic checked the battery and he said it looks good. The car started up no problem with the battery. I will monitor the battery to see if it holds the charge. If not I believe the battery is still under warranty.

 

Battery should be ok for a while, but you might research the effects of "deep cycling" a battery that isn't supposed to be deep cycled, and keep an eye on your voltages. I installed a volt meter on my car after the EXACT same situation and my battery has been fine for 6+ months (although my load tester shows 'weak'). We'll see how it does in the winter (knock on wood)...