Hi so my car has been giving me some issues I fully don’t understand and from what I know my personal mechanic said it’s most likely the tranny. The car when it’s first started it shifts hard into drive and sometimes the D on the dash board that says that the car is in drive starts flashing but it’s rare for it to happen. My car has a check engine light with 4 different codes Po420,po756,p1734, and po780. Any advice on what I can do?
For the transmission, I would take the car to a pro who works on transmission and have him check the car. You also have a code on the catalytic converter which needs to be checked. search this forum, you will find useful information.
It could be a lot of things when the D is flashing I found in previous threads its the shift solenoid but the 04 is infamous for downright transmission failure. You would want a transmission shop access it and see whats wrong. Unfortunately, the data doesn't seem to be on your side, I hope luck is.
You might want to check your ATF condition and level as well.
You would also want to go on google and search those codes up to see common causes.
I ended up doing a tranny flush and my car has been really good no check engine light which is amazing