My 2002 Honda Accord has the CEL go on from an OBD code P0780 which is a shift malfunction. What does that mean and should I care about it?
The CEL wasn’t put there to be ignored…it’s there to tell you if something is wrong. Something is wrong and it’s asking you to have it checked out, so take it to a transmission shop and let them diagnose it.
It’s not a reach to say that it could develop into a bigger (and more expensive) problem if you choose to ignore the warning the car is giving you.
When it comes to transmissions, it is up to you. If you like buying new transmissions and getting stuck in the middle of nowhere on a dark and stormy night, then don’t worry, if you like having money in the bank, then have it checked out and repaired.
The Honda shop manual states as the possible cause a potential defective “Torque Converter Clutch Solenoid Valve - Shift Solenoid Valve A and/or A/T Clutch Pressure Control Solenoid Valves A and B.” No doubt this explanation leaves you no better placed than before. Should you care about it? Well, I certainly don’t. It’s your car, not mine.
Is it shifting ok??? Normally a P-0780 indicates a mechanical problem in the hydraulic system. Usually, when I get a 0780 code I go to the CPC or "Linear" solenoids. That, and the shift solenoids I check. If after replacing these and clearing the codes, they re-appear after test driving, there is most likely an internal transmission problem.