So I feel like I bought a lemon from private party. Bought this thing 3 weeks ago 126k miles $10k. A week later get a check engine light p0894 and p2714. Previous owner says it was working great for him, I assume he cleared the codes before selling it to me. I disconnect battery and light stays off for 2 days then back on then I clear the codes with my code reader and it stays off a week. Couple of days ago the battery goes dead and guages are bouncing all over the place and nav screeen turning off and on so I put a new battery in it. A day goes by and same thing, battery almost dead and guages bouncing around so I check the alternator and its not putting out but 6 volts so I put a new alternator in. All good now so I think the alternator wasnt giving 12 volts and the computer was tripping out and gave me the check engine light. Last night engine light again check engine light so I check it and same 2 codes. I was really hoping it was the alternator sending bad voltage. I cleared the codes again so nothing is on now.
Transmission shift smooth and runs great through all gears except when engine light comes on it wont go past 4th gear. If the tranny is throwing codes should I be able to feel it not shifting right or slipping like it says it is. It will probably be fine with no lights for a week then same thing. I really wish I wouldnt have bought this thing. Hoping I dont need a new tranny. I buddy and I can put 1 in but its a PITA it looks like.
Any input is appreciated!!!!!!!!!!

 

Sounds like you might want to look into replacing the faulty solenoids in the trans. And you're probably right, the seller probably had this problem and immediately wanted to dump it off on someone else. Of course he had the codes cleared right before the sale.

 

The transmission, when the CEL is on will not go into 4th gear purposely. The codes place the trans in limp mode. Im guessing the P/O severely botched up some wiring with something. Check everywhere for aftermarket anything. Possibly a loose ground. Look for the 3 main grounds in the engine bay and make sure they are tight and clean.

 

II found this on another board.

TSB:
SB0034-09
04/07/2009 Engine Controls - MIL ON/DTC P0751/Possible DTC P2714

Lexus IS250 Problem

Model Year Affected: 2007

Drive Trains Affected: AWD, RWD

"The Check Engine Light may illuminate on vehicles with an automatic transmission, with codes P0751, P2714, or P0894 stored. Our technicians tell us these may be "false" codes. Revised powertrain control module (PCM) is available to correct this concern."

You will have to go to the dealer on this one, as far as I know. It's a free repair only if you are under some kind of factory or extended factory warranty. The bad news, it's an out of pocket expense if you're no longer under warranty and does not look like it can be repaired yourself as it sounds like they need to go on board with their computer to do an ECU reflash/reprogram. Unless you can get the Toyota Software and flash it yourself? Apparently though it costs like $200 to reflash at the dealership.

 

I just hate going to the dealership for anything if my car is out of warranty. I also hate paying someone to do something I can do my self. That being said, it looks like I might be stuck going to the dealership but I cant do it anytime soon since Im out of work. I think I'll just keep on clearing the codes when the engine light comes on. Atleast this way I can somewhat diagnose the problem if the tranny keeps operating fine I'll know its a faulty code.

 

flynryan have sort out your issue ?

 

[QUOTE=JeepAss;11510315]flynryan have sort out your issue ?[/QUOTE

he’s not gonna answer ofc
that’s how they are