Strange Engine Check Light Behavior
 

My 90 240SX engine checklight did something strange today. I started to flash 1 blink..2 blinks.. 3 blinks.. all the way up to 5 blinks and then repeat the cycle again. The engine check light has been on for awhile and last week I tried to retrieve the code from the ECU with no luck. I followed the procedure on this forum turning on the ignition till all the dash lights are on then turning the mode screw clockwise wait 2 secs then counterclockwise but the check lamp did not flash.. Also the mode swich that I turned is labeled rpm.. Is this the right switch or is there another one labeled mode? The one that I turned is an adjustment pot I believe for idle. Can someone steer me in the right direction as to how to get the codes? Also whats up with the flashing check light?

sounds like a ufo was in your area, I have heard old o2 sensors will do tricky stuff on the CEL. If the problem returns just check the ecu for code again. otherwise, forget about it and just drive_shift.

I think you've actually left the ecu in the code retrieval mode....

I found out what was wrong. Yes the ECU was still in the on mode. Apparently I had used the wrong procedure to check the code. I rechecked the code and it showed a code 55 which means everything is normal. I reset the ECU and the blinking check code lamp went out. The procedure I used the first time was for the dohc engine and my car is a sohc.