andrewdai

Last weekend, my old but very good Acura TL 2.5 Premium got a CEL on. I pulled the code scanner and it said that this is P0118 - ECT Sensor Circuit High. So, I guessed I could keep driving until the repair shops are open, at the same time I erased the code. After one day CEL was on again but this time it was three codes: P0118, P0700 (TCM) and P1792 (ECT Circuit Malfunction). I also noticed that the car started jerking (or hesitating, could not tell the difference) when I pushed the gas pedal. After ten minutes or so, it no longer jerked.

My question: Could it be only due to ECT sensor going bad that my car jerked? If it is, then I would spend money to fix it. Otherwise, I would start looking for a new car. BTW, my understanding is that the P0700 code is related to P1792, which means once the sensor is replaced, this should fix all three?

Any insight is welcome.

andrewdai

Ok. Let me self-answer this and close this thread.

I changed the ECT sensor which costs like 10 dollars (actually it comes with Coolant Fan Switch as two units so it costs like 5 dollars), and all the three CEL are gone. The gas mileage also improves. It is interesting that this small fix not only dealt with the CEL but also the car jerking.

It looks that the first generation TCM (Transmission Control Module) uses inputs from the sensors and will throw an error code if the inputs are invalid. A defective sensor which in theory has nothing to do with transmission will cause the transmission-like symptoms. The Acura dealer is very correct by saying that "ignore the P0700 - Transmission problem, but focus the code(s) come with it".