Hi All-

I have a new to me - otherwise perfect 2004 LS430 2 Days ago the CEL and Check VSC light came on Scan Tool has only one Error P2757 Car has 171k on the clock and shifts perfectly fine. Cleared code several times only to return.

I would welcome any first-hand knowledge of your particular fix prior to bringing to Lexu$

Thank Thanks!
Tony

 

I am convinced it’s the ECU.1. Check ECU calibration ID

A Lexus dealer or any shop with Techstream can pull the current ECU firmware version.

The 2004 LS430 should have one of the following calibration IDs:

• 89661-50840 → superseded
• 89661-50841
• 89661-50842 → updated lockup control
• 89661-50843 → final revision

If yours is earlier than the “842” or “843,” it is almost certainly your problem.


I’ve thrown almost everything you can imagine at the issue with no resolution. I’ve torn down the transmission and replaced the solenoid, yaw control, sensors, etc.

I can tell from the documented history of my vehicle that the transmission was recalled and replaced. I see the P2757 started appearing not long after.

I can tell you exactly how it gets triggered, too. I get annoyed because it messes with my cruise control and I often reset it. Toyota reman transmissions for the 2004–2006 A761E had:

• updated valve body machining
• updated SLU/TCC solenoid spec (slightly different impedance or flow characteristics)
• updated lockup strategy compared to original factory units

BUT:





❗ Many LS430 models

never received the updated ECU calibration

that matched these updated transmissions.





That mismatch can absolutely cause:

• TCC fail-to-lock
• incorrect slip RPM detection
• P2757 even with brand new solenoids
• intermittent limp mode after warm-up
• “solenoid electrical fault” even though the solenoid is fine

Toyota documented this issue for Lexus GS and LS models, but the 2004 LS430 bulletin coverage was spotty and VIN-specific.