electronic issues (1 Viewer)

[satchel]

A couple of months ago my wife mentioned she was driving her LX570 and warnings started popping up for ahc and something else we don't recall. It happened a couple of times then has been fine since.

I drove it shortly after and 4 times when I pressed the brakes all the electronics went dead (radio/dash), then came right back to life. I noticed during those issues that the voltage Guage was hunting around a bit. I cycled the headlights, which were on, off and on and it went back to solid 14v and no issues after that. The last time it happened I did get the ahc warning.

Checking the battery it did appear like it was going out so we had that replaced. All seemed fine for a month or so but it popped back up yesterday a few times, each time after pressing the brakes. Battery still seems fine, stays at 12.7 when car off and all accessories on (lights/etc).

Thoughts? Alternator seems like my next option and it is staying around 13.7V instead of 14+. Not sure what it should be while running but I would assume 14+.

 

[Zill]

A couple of months ago my wife mentioned she was driving her LX570 and warnings started popping up for ahc and something else we don't recall. It happened a couple of times then has been fine since.

I drove it shortly after and 4 times when I pressed the brakes all the electronics went dead (radio/dash), then came right back to life. I noticed during those issues that the voltage Guage was hunting around a bit. I cycled the headlights, which were on, off and on and it went back to solid 14v and no issues after that. The last time it happened I did get the ahc warning.

Checking the battery it did appear like it was going out so we had that replaced. All seemed fine for a month or so but it popped back up yesterday a few times, each time after pressing the brakes. Battery still seems fine, stays at 12.7 when car off and all accessories on (lights/etc).

Thoughts? Alternator seems like my next option and it is staying around 13.7V instead of 14+. Not sure what it should be while running but I would assume 14+.

Did you check for water intrusion/corrosion underneath the door sills and along the connectors near the bottom of the A pillars?

When the electronics go hay-wire it’s usually that and it’s caused by a sunroof drain clog and subsequent interior leak.

 

[bloc]

13.7-8 is normal charging for our vehicles.

Agreed you need to check under the door sill trim for water. Has it been raining much where you are?

 

[2021 LC200]

Did you check for water intrusion/corrosion underneath the door sills and along the connectors near the bottom of the A pillars?

When the electronics go hay-wire it’s usually that and it’s caused by a sunroof drain clog and subsequent interior leak.

As part of getting water to the a pillar connectors, was your windshield recently changed? The cowl at the bottom of the window can be damaged in the process and not seal properly anymore, letting water in via the HVAC inlet.

 

[satchel]

No windshield change and no signs of water and also no exposure to water recently. Car hasn't even been washed in 3 months.

 

[bloc]

So the brake booster does draw significant current any time you apply the brakes, while it restores the hydraulic pressure in the accumulator. If this pump was going out I could see it drawing too much current, but that should be protected by a fuse.

Personally I’d be focusing on battery terminals (including loosening both, spreading them open to push as far down onto the post as possible, then tightening), and maybe some of the stuff inside the fuse box. Looking for loose connections or similar.

 

[lx200inAR]

So the brake booster does draw significant current any time you apply the brakes, while it restores the hydraulic pressure in the accumulator. If this pump was going out I could see it drawing too much current, but that should be protected by a fuse.

Personally I’d be focusing on battery terminals (including loosening both, spreading them open to push as far down onto the post as possible, then tightening), and maybe some of the stuff inside the fuse box. Looking for loose connections or similar.

I agree on battery terminals, especially if no water at A pillars. I'd also suggest removing the terminals and cleaning the mating surface of the battery lug and the inside of the terminals. I had dirty terminals and replacing the battery did not resolve my issue. Also, could just replace the terminals. At this point you may just need a new set, especially if you've been cranking down on them.