Hi
my check engine lamp is on I have an Accord 90 2,2 i and i see the code on PGM is 4 lång and 1 short blink

Is this for Oxygen (Lamda ) before Cat or? canI check if Lamda is Ok with elictrical instrument

Peter

 

4-long & 1-short is code 41 - elecric heater built into the O2 sensor. In 1990 there's only one sensor.

Unplug the O2 (lambda) sensor & look for 2 same-color wires (black?) on the sensor. Resistance between those should be 10 to 40 ohms. If it's not, you need a new sensor.