Hello.

History: In the July timeframe I posted about the ECT power light flashing on my dashboard. The company that replaced the automatic transmission said they couldn't find anything wrong but offered to remove the bulb so I would not be distracted by the flashing light.

Yesterday in addition to the ECT flashing light, the Check Engine light appeared on my dashboard.

I was out of state and went to my brother's long time repair person who performed a check of the computer and gave me the following information:

PO125 - Insufficient / Time or Temperature for Closed Loop - most likely repair is to replace engine coolant thermostat
PO715 - Input / Turbine Speed Sensor Circuit Fault
PO758 - Shift Solenoid "B" Electrical

My brother's repair shop said all 3 Codes can be fixed and then recommended I stop driving the car until the repairs are done. So, the Lexus is in the driveway while I bum rides to/from work.

My repair shop said he can do PO125, replace thermostat, which is scheduled for 26 Sep but he doesn't believe the other two repairs are even possible.

My question to the Forum, can PO715 and PO758 error codes be fixed (in a reasonable time / at a reasonable price) and are parts available for fixing PO715 and PO758. OR is the repair guy correct in saying the repairs are impossible.

Thanks in advance for sharing your expertise.

 

Why wouldn't the repairs be possible? It seems straight forward based on the fault codes and far from "impossible"

The 2 codes should be fixed with a new speed sensor(PO715) 89411-50010, and a new "B" solenoid(PO758) in the transmission. As long as your ECU is in good working order that is the route I would go. You may want to get another opinion from a reputable shop.

 

Nothing is impossible. The only thing I can think of why "The company that replaced the automatic transmission said they couldn't find anything wrong" is, I think there was an upgrade on the '95 ECU. (something with the shifts) I'm not saying 100% cuz I only have, and had 93-94s. Someone else might chime in on that. But even if those two parts were bad, they can be changed.
Do you have any warranty on the tranny?

Edit; I did just notice the '95 ECUs did have an upgrade on them. Has there been any rebuild to your ECU? Does the car shift, and run, ok even with the codes?

 

thank you. I will start my research to locate the parts you reference. Thank you for sharing your knowledge.

 

At times, the shifting is delayed and then rough when it finally shifts. I'll see what I can find on finding an upgraded ECU. The transmission that was installed late June had 62,000 miles from a 97. The warranty has expired (of course) although I reported the ECR flashing light at the end of week 3. Ugh.

 

The codes do make sense. If the ECU can't tell what speed the engine/trans is at due to a bad speed sensor then it won't shift properly. A bad shift solenoid also has similar symptoms.

ECU can also not be ruled out, especially if it is original. I would probably try to fix the codes before messing with the ECU.