Hello,

I have 1991 Honda Civic DX 1.5 Hatchback car. It's been giving me headache for two weeks. It starts normally then after driving around 20km (less or more) it stops itself. I leave it couple hours then when I try to start again it starts. It's happened 7 times so far. A mechanic said fuel pump relay (Main relay) problem. I took 2 relay from junkyard and replaced it but the problem is continue. When it stopped I have checked the error its code it was blink(short) pause blink(short) pause blink(short) so on.. The error code list says: Primary oxygen sensor- Defective circuit or unplugged/ Defective sensor . So, I am going to get change oxygen sensor which I have spare. Which part can cause this problem? Oxygen sensor? Ignition coil? Crank sensor? Does any one have an idea about this problem?

TX.

Replace the Ignition Control Module (ICM) and coil:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-4.html#post265896

The oxygen sensor lmay need replacing but it's a "side show." After replacing the ICM and coil, reset the ECM and the oxygen sensor code may go away. If not, replace the oxygen sensor and reset the ECM, again.