Originally Posted by Microbiology
I own a 2001 toyota camry, and recently a check engine light came on. I took it to the dealer and they cleaned up the transmission oil. After a week, the light came back on again, with the same code P0770.
I took it to the dealer for the 2nd time, they told me they couldn't find anything wrong, and that there were no shifting problems. And they told me to recheck this on next service to see if only one code would require further diagnosis.
What are your views on this?
When the computer generates PO770 it's trying to tell you that it is seeing a problem with the torque converter clutch lock-up engagement either not locking or releasing when it should. There is a shift solenoid that is commanded by the computer to direct hydraulic pressure through the valve body to the torque converter lock up clutch at certain speeds. The two most common problem areas with this code would be either dirty transmission fluid blocking flow to the clutch or a faulty solenoid valve.
When you say that they 'cleaned up' the fluid, what service did you have? A drain & fill would be pretty ineffective, as it doesn't replace close to the whole amount of fluid in the trans. If the torque converter was indeed performing normally when they test drove it, then you might have an intermittent problem with the valve.