Tilt/Telescopic ECU Parasitic Draw - Now Alternator not Charging?

[RunMan]

Long-time lurker, first time poster. Have had my 2000 LX470 for about a year now. Love the thing. 156,000 miles, in good condition.

I have been having some electrical issues since I bought the truck. Alternator crapped out about four months in. Replaced it (OEM reman) and the battery (interstate group 24 AGM) and that seemed to fix my issues . A few weeks ago the battery died after a week or so parked. Tracked down a parasitic drain from the Tilt/Telescopic ECU. I unplugged the ECU and the drain disappeared. However, after unplugging the thing, my alternator is no longer charging the vehicle. It usually puts out 13.8-14.5 volts. When I start the car, the vehicle is reading around 12.0V. I plugged the Tilt/Telescopic ECU back in. The draw returned, but the alternator is still not doing its job. I hooked it up to Techstream and I am getting only one code: B1213 (Tilt/Telescopic ECU not responding). This code is not new - I had it before I unplugged the Tilt/Telescopic ECU.

Did unplugging the Tilt/Telescopic ECU mess up communication with my other ECUs? Is this just a coincidence? I'm a little bit at a loss.

 

[juicemode]

I am not sure this will help your cause but my LX came to me with a leaky windshield that allowed water to corrode a few of the contacts on my tilt/telescope ECU. I found a very clean used one on eBay and just did a direct swap to fix my tilt/telescope inoperable. The used part was $50. Unfortunately in my case the windshield is much taller order.

 

[RunMan]

I am not sure this will help your cause but my LX came to me with a leaky windshield that allowed water to corrode a few of the contacts on my tilt/telescope ECU. I found a very clean used one on eBay and just did a direct swap to fix my tilt/telescope inoperable. The used part was $50. Unfortunately in my case the windshield is much taller order.

Thanks for sharing. I also had water coming in via the sunroof, which is likely what damaged the ECU in the first place. I'll add that the tilt/telescope has been inoperable since about two months after I bought the truck. I don't really need the tilt/telescope so I figured I could just disconnect. I guess not. I may replace if I can't find another workaround.

 

[RunMan]

Absent any advice from folks here, I plan to move forward with the following plan of attack. I will report back after I work through this list.

1. Recharge battery to typical voltage (12.6V). It is down to 11.7V after many efforts to hard reset the ECU via disconnect and letting the engine idle for some time.
2. Replace fuses in charging circuit. For me, this is the 7.5A ALT-S fuse and the 80A fuse in the engine bay fuse box.
3. Replace T&T ECU

After each step, I plan to "reset" the ECUs through battery disconnect, and allow ample time for the ECUs to power back on and relearn before starting up the engine. So far, the only symptom is the lack of alternator output (and a somewhat rougher than normal idle).

I am hoping I did not cause any damage to the ECM that would require replacing that part, but I suppose it is possible. Techstream seems to be reading all ECUs besides T&T just fine and is throwing no codes (aside from the aforementioned B1213). Techstream shows the 11.7V output from the alternator for what it's worth. It is also possible I fried the alternator in some way when I unplugged the T&T.

 

[RunMan]

Blown ALT-S fuse. $0.30 fix!