I've just bought a 98 civic ex 2dr but failed the inspection because of multiple faults (a lot of PO__ faults) without showing check engine light when car is running (check engine light comes on when switch to ON then OFF after 3 seconds) there's no issue driving the car. I checked the ECU part number to make sure it is for a 98 and it shows that it is for a 98. I also noticed that the exhaust manifold has a cracked and hear that it's leaking. I will post the PO__ faults when I recover again with my OBD 2 scanner. Anyone who has the same problem and how it could be fix. PLEASE HELP

 

Those are old stored codes. The CEL goes out when the situation causing a code goes away, but the code remains stored. Make a note of them, then clear them (either with scanner, or disconnect battery) (*). See if any return. The cracked manifold is likely to cause O2 sensor codes and runnability problems related to false readings from the O2 sensor when oxygen leaks in the crack.

(*) Note that after clearing the ECU, before going to smog check again, you need to drive about 20 miles to get rid of the "not ready" code.

 

Today I cleared all the faults using my OBD 2 scanner and drove it for about 80 miles and when I check the fault the same fault came out but what surprise me is that when I was driving I did not notice any check engine light that came out. This are the faults that was scanned PO700, PO740, PO301, PO302, PO303, PO300, P1456, P1399. About the readiness,the HO2, O2, EVAP SYS, CATALYST, COMPREHENS, FUEL SYS and MISFIRE are all ready and one more that I've noticed is when I turn the ignition to ON the Check Engine light, Oil light, Seat Belt light, Brake light, Park light, SRS light and Neutral light are ON and after 2 to 3 seconds I hear a clicking sound under the passenger side then the Neutral light and SRS light turns OFF and when I start the car the Oil light and the Check Engine turns off simultaneously. what I don't understand is, after 2 to 3 sec it is suppose the Check Engine light to be OFF if there's no fault instead of the Neutral light and with this faults it is suppose that the Engine light stays ON. Next time I'll try to replace the ECU. Any idea whats the problem?

 

Any Idea out there what's wrong with my civic? Tried to contact the previus owner but can't get hold of him I think he has already changed his number. Before changing or buying parts I want to know some ideas coz I don't want to spend more money on this car....please help