Check engine light but ECU red light not flashing

Hi everyone, I have a problem with my 1990 honda integra my temperrature gauge goes straight to hottest even on cold starts and you can feel the engine cold, idle is around 1500rpm, check engine light is on, all this happend after changing the water pump, I bled the coolant system and i think i might have a leak in the Fast Idle Thermo Valve, cause i can see a small coolant leak under (but I don’t think that should give me this problem cause it didn’t give me this problem before when I had a small leak on the radiator hose, but my problem is how do I get the Engine code cause my Integra is OBD0 it has a red light on the ECU that will flash codes when the check engine light is on on the gauge, and my problem is that red light is not flashing codes, I also tried looking for that two pin plug under the passenger footwell and short it with a wire to get the check engine light on the gauge to flash codes but still just staying on its not flashing, could it be that the light it self is not working? I have no idea please someone help me

what position is the key when you try and look at the red light? use a paper clip to jump that connector. its easier…

yes i used paper clip, used wire, used a circuit bulb i made, the key is on the ii before crank :frowning:

update: everytime I start the engine then switch it off the red light on the ECU will blink a fast one at the same time i switch off the engine, its confirmed that the light is working but does this mean I have no trouble code?
update: my idle seems to be at normal idle now, i tried rebleeding the coolant system, i might have left some air last time I bleed it.

extra info: could it be that my temperature gauge is faulty? cause I recently change the gauge on my car the same time i changed the waterpump, could it be that my gauge is faulty? also I replaced the small bulbs on the gauge with led.

your problem is weird…

i would say grab the code from when the engine is on and see what it is. your cel wouldnt be on if you didnt have a code.

i wish the ECU is giving me that code so I can sort it out, i dont understand why would the CEL be on and the ECU would not give anything :frowning:

you said the ecu would flash when you start the engine and turn it off. do that and get what code it flashes for and we can work from there. otherwise, i dont see how you can have cel but no code on the ecu…

my next idea would be to swap the ecu with another one and see what happens then if all else fails, get a chipped ecu and a copy of crome and pull the code that way.

you dont really have too many options with a crazy issue like this. as long as your car is running normal for you to drive around with no issues then i would just say leave it alone and get a water temp gauge so you can monitor it.

its only flashing one quick flash when i turn it on and off and its not repeating the flash, i’ll try at that thanks mate.

yeah im sorting out that temp gauge priority wise and its easier than this crazy ECU problem.

maybe that 1 flash is a code. i dont have my code listing on hand and i have no idea where it is. but you should check…

Code 1 is Oxygen Content, check O2 sensor, heater and O2 sensor circuit.

When you did the thermostat, did you make sure the thermostat housing ground(s) where reconnected properly? 94

any update?

ok apparently you can’t change the check engine light bulb to a led bulb, everything didn’t give me any problem when i change them to LED except the engine light,so i change the check engine light back to a normal bulb and everything worked fine, so my only problem now is that temperature gauge, cause i’ve change the temp sensor, temp sender, the only thing left is that gauge, hopefully i can find a gauge here before the holidays its australia day on the 26th lol

[QUOTE=stukenante2;2284748] the only thing left is that gauge,[/QUOTE] Or the wiring between the ECT sending unit and the gauge, easy enough to test, all you need is a 12V test light, [NOT the LED type] access the ECT sending unit lead/terminal behind the cluster, with the ign. on and the test light ground clip grounded touch test light probe to the temp. gauge terminal, the gauge will go up, [if working] how far up it goes will depend on a few things that make no diff., all you need to see is if it goes up or not.

If not, replace the gauge, if it does go up, find the break in the ECT sending unit lead. 94

fixed the gauge everything works fine now, although just curious if the fuel gauge really doesn’t drop when you switch the car off, i know i have full tank cause when i filled up my car it overflowed cause my old fuel gauge is not working too but with the new one when i installed it the fuel gauge crawled up to full because my tank is full and i can see it drop by the time i use the car but it doesn’t drop to Empty when i switch the engine off like the other cars I used to own, is that normal for the G2 integra?


Sorry, not sure about your Integra, but on many cars, [MM&Ys] the gauge does not fall when ign. is off, and on others it will.94