'96 Ls400 Stuck In Park, Abs Light On, Battery Drained

[auctionjunky]

Hello, this is a 1996 LS400 with 220k miles. I bought it in LA at an auction, so I dont have the repair history. It should be noted that it's usually over 100 degrees this time of year in Vegas, and this car was spoiled in 80 degree So Cal weather. After a 120 mile drive, parked it overnight to find the yellow abs light on and the vehicle stuck in park in the morning. The red battery discharge light might be pulled, it doesn't come on. I used the override button to put it into drive and get it back to Las Vegas. 15 miles from home, the battery died. Tried jumping the vehicle, but it wouldn't hold a charge. Pulled the positive terminal and the vehicle wouldn't stay running, indicating bad alternator. Towed it home. Charged battery for 45 minutes, turned it over with all accesories on and the vehicle stayed running, but the abs light is still on, stuck in park.

The brake lights work, including the 3rd brake light. Checked all fuses under dash and on driver fender area, no blown fuses. I don't know how to properly check the relays so I left those alone. When I go to put it into gear, I hear clicking from under the steering column, might be the brake switch. Measured voltage with vehicle off, about 12.55, with vehicle on, 12.2. Sounds like the alternator is bad. I don't see any moisture from the power steering pump on top of the alternator. I'll just remove the alternator and have it checked out.

My real concern is the abs and stuck in gear issue. Is the alternator or weak battery related to the abs light and stuck in gear issue? And can a defective brake switch still trip the abs light even if the brake lights are functioning as they should?

Any help is greatly appreciated, :)

[datarecovery]

On my 1992 SC400, the problem of stuck in park also happened. had to remove the Airbag fuse temporarily to allow "normal" function.

Turned out to be a bad ecu.

I did not have the discharge problem you had.

You need to go through the diagnosis procedure to see which circuit is "leaking" voltage.

Also check alternator output with a voltmeter.

[Exhaustgases]

I think brake light switch controls the park lock solenoid. And likely has something to do with ABS and Trac as well as cruise control. When running, the voltage across the battery terminals should be around 14 some volts.

[auctionjunky]

thank you both for the great advice. come to think of it, my cruise control is out as well. do you guys think the stuck in park issue be related to the possible bad alternator or are they two separate issues?

[auctionjunky]

did the circuit test, no drain detected. also had alternator checked at the auto parts store, passed, so the alternator is good. not a drop of fluid on the alternator, looks fairly new, denso reman. i'm leaning towards maybe an ecu issue or cruise control module. or both. should i go after the cruise control module or ecu, first? note: when i connect a diagnostic tool to the service port, it registers, and it reads trouble codes just fine. does that rule the ecu out? This is a head scratcher, when you run across a head scratcher, don't rule out the ignition switch... now I'm all over the place.

[auctionjunky]

took ecu out today, no capacitor leaks of any kind, the board looks fantastic. next up, checking wiring along left side of trunk lid. if that's a no go, going to check ignition switch / wiring.

[auctionjunky]

wires along trunk look like-new. checked battery at auto parts store, it tested good. cleaned and inspected all connections at alternator and fuse box / battery. ground connections look good.

[auctionjunky]

fixed.. timmy.. ra and 381 inspired me to actually pull each fuse instead of relying on the TEST LIGHT ... ecu fuse (driver kick panel fuse box) second row up, 1st fuse to the far left 15a blown... replaced it and all is good. thanks for your input everyone.. i spent like 20 hours on this car because i was convinced it was a major issue that knocked out so many things at one time .. lol.. i spent zero dollars.. just replaced a fuse.. calling lexus to cancel my order for a shift solenoid

[sha4000]

The question is why did the fuse blow?

[sadclown]

The problem may be caused by a malfunctioning Transmission Shift Solenoid.

[bobby62914]

Once I found the drivers side fuse box this thread was fantastic. I replaced the ECU fuse and my problem was corrected. I also know why the blew the fuse.

I am dissatisfied with the reception with the factory power antenna so I decided to install a small high-gain antenna. The antenna needs 12v so I was looking around with a meter for a constant 12v. Never did find 12v.

This is my first post but I have used this resource a few times.

I bought my first Lexus, a 1997 LS400 with 153,000 miles, a few weeks ago and I am hooked. I can't wait to get a newer one.