How to retrieve codes OBD (Not OBDII)

How to retrieve codes on a 95 and older Nissans. There is two styles of ECUs. One has a switch one has a twist style knob. The early style is switch.

Put the ECU in mode 3 and count the LED flashs.

  1. Access the ECU, under pass seat normally

  2. Start engine and warm it up.

  3. Turn diagnostic selector in ECU fully clockwise.

  4. After the LEDS have flashed 3 times turn diagnostic selector in ECU fully COUNTER clockwise.

  5. Now read the code from the flashes.   55 is NO codes.

Pages 37, 38 and 39 of 94 VG30e FSM

VG30e ECUs from D21 and WD21s.

92 and 93 ECCS "Check Connector" looking for my Consult port.