Trans Code P1730

[Arroz]

Hello everybody! I'd like to see if anyone else has any ideas. My 2000 fwd RX300 (145K) has a P1730 code. It drives and shifts fine and I've tested both speed sensors and they are within normal limits and so is the wiring to the ECM. I know the next logical step is to replace the ECM to see if that is the problem but can't see spending a $100 bucks just to see if that is the problem. I know these have a history of transmission problems but don't the sensors just read the teeth going by? Any ideas or suggestions would be appreciated. thanks.

[code58]

Curious as to where you got that code. I don't find it in the Lexus specific codes but rather in the Jaguar specific codes. Doesn't seem to show up at all in the generic codes.

[Arroz]

It is from the Diagnostic manual

[code58]

That's interesting. I checked 2 different OBDII sites and it didn't even come up on Lexus specific. I have the manual on CD but didn't have time to check it.

[Arroz]

Anyone have an ECM/ECU they can let me borrow?:) I did notice today that it won't go into O/D which is still not definitive on the problem being the transmission or the computer.

[Arroz]

Well, I replaced the transmission and the P1730 code remains and still no overdrive. I am at a loss. Do I throw more money at it by buying an ECM?

[lenore]

Are there other codes present....(secondary codes.)?

[Arroz]

Nope, no secondary codes.

[lenore]

I wonder if you have a wire harness or plug connection that is corroaded....I would do so searching there.....a intermittant plug could cause a false count.....See if there is any corrosion inside the plug to the sensors....and trace the harness back to see if it got nicked or damaged...My thought is the cpu is fine.

[Arroz]

I have run continuity check on all wires between trans and ecu and they are all good. I've checked for corrosion on the speed sensors and respective plugs. I have also been under the impression that ECM's rarely go bad. What is the consensus on maybe a faulty torque converter since I reused the old one?

[lexfix]

I had the same code. Both sensors tested ok. I read on another forum to switch the sensors (their both the same part) and see what code comes up, a P1725 for me, so that told me which sensor was bad. So just taking it out and testing the sensor doesn't work, the sensor could still be bad even if it test's ok. I hope this helps someone!!