Greetings TTF, I am trying to clear a DTC from a 1990 Sentra, 1.6L TBI (code 13) Alldata is telling me to put the ECU in mode 4 with the KOEO, then turn the ign. switch off, and the codes will clear. After doing this I checked for a code 55 (no dtc's) and stil... Login to read more.