Has anyone ever got a check engine light after changing out a dying battery for a new one? I just changed the battery in my 94 es300 and now the check engine light is on. The car has 97k original miles on it.

I disonnected the battery over night again, tried clearing out the code with the obd II scan tool at autozone this morn, and the code come right back. It sounds like a KAL pwr feed for the engine ecu.

If anyones had a similiar problem what did you do to fix it? I know if I take it to the lexus dealer theyll want to change out the ecu for some outrageous price that wouldnt fix it anyways.

Thanks...

So no one else has ever has a cel come on right after changing out a dead battery? Car runs fine, and I got voltage at the battery back up ecu pin. Not sure what else it could be. How often to the ecu's go bad?

Trying to help--this from another site


P1600 ECM BATT Malfunction (Toyota)
This code means the ECU is not getting battery power to one of its terminals, the BATT terminal. This is what keeps the ECUs memory from being lost when you shut off the car. Could be the ECU, or it could just be the power supply to it. Check the EFI fuse and make sure its tight and not blown. The BATT terminal on the ECU is the 2nd from the right, top layer. It should have 12 volts on it. Try wiggling all the ECU's wires while the car is running. You probably just have a loose connection.

Thanks, I checked the ckt. Got batt back up power with the key off. I went to advance auto this time to use their tester, instead of going back to auto zone, they tell me that any codes related to the cel in the 1000's are manufacturer specific and can only be cleared by the dealer. Does this sound correct to anyone? Leads me to believe the ecu needs to be reflashed. Ive tried repeatedly to clear it myself by pulling the fuses and disconnecting battery, but no luck.

Did you find a problem with the circuit? If you found a problem and fixed it, the check engine light will reset itself after a few driving cycles.