What are the most common faults in the ECM for the 2000 Toyota Echo auto?

Answer 1

p0420 is the only common fault I know of for the Echo. The software is too sensitive, this could possibly be fixed with a firmware upgrade which is exactly what Toyota did for the Rav4 which had the same problem, but in the case of the Rav4 they issued a recall. The Echo has NOT had a recall for this issue. The car will often run fine, pass emissions tests, and get normal fuel economy even after the p0420 code comes up. The dealer will charge $1400 to put in a new catalytic converter (they replace the full assembly from engine to tailpipe). If you decide to save by using an aftermarket cat the p0420 code will in many cases will come right back. Of course the code can be caused by other things too like O2 sensors or MAF, but often replacing these will not be enough to keep this code from coming back.