Hey all

My wonderful girlfriend bought a 2001 LW300 Wagon 3.0 v6 Auto from a Junkyard back in May (When I totaled her car and shattered my hip). It’s got approx. 239,000 miles on it and has been a great car so far (other than not starting the day we brought it home, due to a faulty crank position sensor. Fixed that one with a busted hip four weeks out of the hospital lol).

She parked it a little while ago due to it starting and then going into limp mode. Had two codes can’t remember what, that pointed us in the direction of the throttle body replacement. Along with about four other codes.

This week we attempted to get it going again. Picked up a low miles JY throttle body, swapped it on (hammered the nuts into the studs so we could remove the studs and replace them with bolts), and replaced some spark plugs while we were at it. (Removed GM ones, wondering how long those were in there). Hooked up jumper cables, turned the key and the car fired right up. Had the battery charged and tested (the car DID sit for a month or two), tested bad. Replaced with a used battery from another car (same CCA, CA, and Group Size), and she ran. Took it around town a little bit, filled the gas tank (stored almost empty), filled the tires, it was driving like a dream. Brought it back home because it needs tires and that’s next weeks project.

My lovely lady went to start it this morning and said it wasn’t cranking or anything, but that when she turned the ignition switch off (no key, it’s a JY car), the CEL and Change Oil lights stayed on, along with the light on the steering wheel Cruise On/Off button. Even though the car was completely off. She was in a hurry so she left it like that not knowing what to do.

Fast forward to tonight. I get home and go to look at it, sure enough no dome lights, no cranking, nothing. Checked battery voltage and it was 3.7 or so. Hooked up jumpers to my corolla and everything lit up right away. Started it right up as well. The car runs awesome, all the gauges and electronics seem to work, I let it idle for a few minutes as well to charge up the battery.

Turned it it off and all the lights turned off. Then the SEL, the Wrench, the Oil Change, the airbag, the battery, and the oil pressure light turned on. Pic attached. It looked like I’d turned the key to accessory. But the radio, the gauges, none of that was working.

Scanned for codes and ive got four:

U2105 Loss of Communication with ECM
P0103 MAF High Voltage Output to ECU
P0443 Malfunction With Purge Control Valve or Short in Purge Control Valve Circuit (I’ve got a busted connector that accounts for this one)
and P1780 Transmission Control Switch Circuit is out of Self Test Range

I pulled the BCM/ECM/Cruise fuse under the hood, so that the battery doesn’t die (this shut everything off for me). what could be causing this? Where should I look? I’m stumped.

Additional information:

the cooling fan doesn’t turn off, so we usually just pull the fuse for it when we aren’t driving the car

the transmission did start to shift a little hard when it’s really hot. Was planning a new filter, with some fresh fluid and some Lucas. At 239k it probably could use some service.

Theres a strange high pitched whining sound from the throttle body with the key in the on position (or now, all the time). This was like this with the old throttle body as well as the new (used) one.

TL;DR:

01 lw300. Turn the key off and the gauge cluster warning lights all come on. Pulled the ECM/BCM/Cruise fuse and they shut off. Car runs awesome with the fuse in. U2105 among 3 other codes.

With the lights on and the key completely OFF

 

Sounds like

1) huge parasitic drain from somewhere you don't yet know about (as opposed to the cooling fan which you do know about)

2) The fact that but the way you described it was that everything goes out, then some lights come back with the key off sounds like a flaking BCM. What is the odometer reading?

The u2105 is as you know, lost communications with ECM. This may be related to a power issue for the ECM or BCM , or possibly a ground issue with one of the modules losing its ground. Check to make sure the ECM is firmly bolted in place. Same with the BCM. Since this is a communications error, inspect all of the multi wire connectors to the BCM and ECM as well as the pins 4 signs of a bad connection and or corrosion. I expect that our L series expert we'll be along shortly.

 

derf,

First of all, thank you for your very timely response. I appreciate your help already.

Parasitic drain was my first thought. Usually I can isolate the problem circuit by pulling fuses until the problem stops. Then can figure out what the issue is in the circuit. The only fuse that turned the lights off was the ECM/BCM/Cruise fuse hence why we pulled that one. Even pulling the other BCM fuses (marked B+ and BCM 2) didn’t solve the problem of the warning lights turning off.

Odometer reads 239,xxx and has worked since buying the vehicle.

Ive read on here (correct me if I’m wrong), that when the BCM starts going south, it causes issues with interior and exterior lights, radio, other things like that. I’ve not had any of these issues as of now, aside from everything turning off when I shut the key off, then turning back on and staying on. Not ruling out the BCM, but what’s the best way to test it?

 

I will look at this when I get home tonight. No dash lights come on in the accessory position just the radio and the wipers work. All those lights come on in ignition only. Is the steering column all apart to start without a key? What about the security light? Did you do a relearn on the jy throttle body?

 

the steering column plastics are off and ignition switch is out to start without a key. I can send a picture of this when I get home tonight.

Have never seen a security light as long as I’ve owned the car. Definitely not on now.

How would i do a relearn on the throttle body? I would think everything would’ve reset when we replaced the battery, but I’ve been wrong before lol

 

Been a couple months. Still having some issues.

the problem with the lights not shutting off happened to be an ignition switch issue.
the problem with the codes (most of them) happened to be an ECU failure.
I kept getting more and more codes until finally one day it barely started, and a p0606 or similar code came up indicating ecu failure. Swapped with a junkyard ecu and the vehicle runs smoother than it did before.

however:
I still have a few codes
One is the purge solenoid connector being busted
one is a Mass Air Circuit Open code (we replaced the mass air flow sensor?)
one is an o2 sensor code
and one is P1780.

we’ve also got a b1001 (from what I can find online it’s an SRS code? Likely because it’s got a JY BCM in it)

the issue is

I can drive the vehicle through town all day long and it’ll be alright. I did about 40 miles in town today and all went well.

I take it on the freeway (about a 9 or 10 mile drive) and after about 6-7 miles, I’ll lose all throttle response, it’ll kick itself out of cruise control, and I’ll essentially just be coasting.

At this point I’ve got to take it out of drive (either neutral while coasting, or pull over and put it in park) and turn the vehicle off, then restart it. Sometimes when I do this, the vehicle dies immediately. Other times, it’ll stay running but really really rough. I can usually drive it home like this but the transmission (which has been shifting beautifully since ECU replacement) will SLAM itself through the gears when shifting.

Honestly I don’t know Where to look next and I’m really trying to keep this Saturn going because my lady and I both love it, but it’s looking like she’s leaning more and more towards selling it every day. I’ve been giving her rides in my corolla though and she hates that car