Transmission woes....how to proceed?

[es300keith]

I own a 1996 Lexus ES300 with 180k miles on it. I bought it from a neighbor for $500 because he wanted it out of his driveway. His son used to drive it, but since the son purchased his own new car, there it sat. I test drove it and the car ran incredibly, the transmission shifted well and everything, but it had a check engine light, so I figured I could get to the bottom of it. I'd have to because the State of Virginia requires annual inspection.

So I bought the car, did some research, bought an OBD II code reader and found a code P0773. I replaced the solenoids on the valve body, reassembled transmission and the code went away.

VICTORY!

Or so I thought until I put it the car in gear and nothing happened. What I discovered after taking the valve body back off is that I had torn just a corner of one of the valve body gaskets. Maybe this was the issue, so I order the gaskets online, install them and the A541e transmission comes to life.

VICTORY!

Once again, a premature celebration was quelled by shifting that was intermittent. Eventually, D, 1 & 2 wouldn't offer any response. Reverse would, but only after a little bit of a lull. I got the following codes when pressing the accelerator in drive:

P1705(Direct Clutch Speed Circuit Fault)

P0500(VSS MALFUNCTION)

I was able to clear both codes and they haven't returned, but my trans still will only shift in reverse. I'm not sure how to proceed, so I thought I'd check in here for suggestions. If I have basically ruined the transmission somehow, I'm open to having it replaced or rebuilt, but I'd like to take this opportunity to learn something. I'd like to know what you'd do in a case like this, from grease monkeys to check writers...how would YOU proceed?

Thanks for any and all responses.

[es300keith]

So I was able to clear the P1705 code and to this point, I have not been able to recreate it, which is good I suppose. The only code I'm getting, once I accelerate over about 2500 rpms is the P0500. Any and all suggestions are welcome.

[OU1]

I had a similar problem, my 94' was throwing the PO500 code.  and was having a rough time shifting and over revving itself.  When I replaced the VSS it only temporarily solved my issue.  in the end I had to do a transmission swap as I found that my transmission gears were toast.  and my transmission would randomly shift into 1st or 2nd going 60 MPH down the highway causing my RPM's to redline within seconds.  have you attempted to replace the VSS?  and inspected the VSS plug and wire for any noticeable damage?  also have you inspected your shifting cable to insure it hasn't slipped?  have someone shift your car through the gears while you watch the shifting cable to see if it is even shifting through the gears.

[es300keith]

5 hours ago, OU1 said:

I had a similar problem, my 94' was throwing the PO500 code.  and was having a rough time shifting and over revving itself.  When I replaced the VSS it only temporarily solved my issue.  in the end I had to do a transmission swap as I found that my transmission gears were toast.  and my transmission would randomly shift into 1st or 2nd going 60 MPH down the highway causing my RPM's to redline within seconds.  have you attempted to replace the VSS?  and inspected the VSS plug and wire for any noticeable damage?  also have you inspected your shifting cable to insure it hasn't slipped?  have someone shift your car through the gears while you watch the shifting cable to see if it is even shifting through the gears.

Good suggestions!

I'm having a devil of a time finding the VSS plug, but when I locate it, I will definitely take a closer look. Where exactly is the shifting cable? I have no idea and Googling it brings up nothing.

[es300keith]

...and FINALLY, the dreaded P1600 error. Engine control module (ECM) -supply voltage. This is obviously beyond my ability. Gotta hire someone or sell it as is.

[Hoopes999]

the ecm is most likely the problem, find a used one with the same part # and swap it out

[OU1]

On 5/20/2016 at 6:05 PM, es300keith said:

...and FINALLY, the dreaded P1600 error. Engine control module (ECM) -supply voltage. This is obviously beyond my ability. Gotta hire someone or sell it as is.

Sorry for some reason it did not notify me that you had responded.  As for the shifting cable it's the wire that's running over the driver side of the motor and connects on the front part of your transmission between the bottom of your radiator and transmission.  There should be a cable that is connected to an arm that is attached to your transmission.  The arm is what controls gear shifting within your transmission.  And for the ECM go to a junkyard and pull one or have 1 pulled.  There are a few different vehicles you can pull it off of.  Look for vehicles between the years 92-96 that have a 1mz-fe motor in them.  Replacing an ECM isn't terribly difficult.  It's located behind your glove box couple screws and some wiggling will give you access to your ECM