Hi. I have a 90 Civic DX with 152K miles. The Check Engine Light now comes like clockwork after driving 6 or 7 miles. This has been happening for about a week so I took it to a mechanic yesterday. I could tell he wasn't real familiar with working on a car so old. He then pulled up the carpet on the passenger side to read the code after making a few phone calls. We both watched and kept getting 1 red blink followed by a pause, and then 15 quick blinks, then the process would repeat itself over and over.

He then called an ex-honda tech and he said he thought it was error code 1-15 but didn't have his old diagnostic book with him. The mechanic told me there was no code online for a 1 dash 15. He said he thought we were getting 2 codes, a code 1 and a code 15. He said according to what he was seeing online it looked like an oxygen sensor (code 1) and 15 Ignition Output Signal Circuit (code 15). He said he wasn't exactly sure about the code we were seeing and exactly how to read it, but thought it was a 1 & 15.

Any help you could provide would be much appreciated. This mechanic said he was covered up, and probably couldn't work on it till next week sometime. Unfortunately, I'm not real confident he knows excatly what's wrong or how to fix it.

TheTXGreaseMonkey helped me out back in Feb of 2010 and diagnosed my problem perfectly. Sure hope you're still out there. The car seems to run and idle fine, but it sometimes seems that the engine revs up higher (idles higher) after I turn it off and restart a few minutes later. Thank you.

Also, when I restart the CEL does not come on again until I've driven it for a few more miles. It really seems to run fine for the most part, but it's just very alarming when your Check Engine Light keeps coming on.

You have two items that need attention:

. Replace the oxygen sensor, for the Code 1:

https://www.askmehelpdesk.com/cars-t...tml#post223376

Code 1 is causing the CEL to come on, once the engine warms up and comes out of "open loop" mode.

. Replace the Ignition Control Module (ICM), for the Code 15:

https://www.askmehelpdesk.com/cars-t...tml#post265896

Ensure that you apply a thin, even coat of heat transfer compound to the back of the ICM or it won't last long. This is an excellent time to also replace the coil, if it hasn't been changed in the last 10 years or 120,000 miles.

Thanks TX. I'll definitely replace the oxygen sensor ASAP. Would that be an expensive repair?

Also, I replaced the ICM back in Feb of 2010, and you helped me diagnose that one too, right on the money. Sounds like my mechanic didn't apply a thin, even coat of heat transfer compound and it must be getting ready to go out again.

I really appreciate your help TX, you're the best!

It shouldn't be too bad--just make sure you buy a Denso oxygen sensor.

Ok, I see auto zone has bosch with a 12 mo. Warranty and denso with a 3 mo. Warranty, and your sure about going with denso over bosch? Also, I'm wanting to send you a little chesse for your help, hope I can use paypal? Thank you.

You do not want to use Bosch. It won't work well at all. Shop online and get the best price you can for a Denso oxygen sensor (O.E. type, not universal). Honda uses Denso oxygen sensors.

Thanks for the consideration--yes, PayPal will work fine.

Thank you. I will definitely follow your advice and have sent you a thank you through paypal. Have a nice evening!

Notice to others: If these good people answer your questions and help fix your problem, please be kind enough to send them $15-$20 through paypal. After all, they did take their time to respond, and that's the very least you can do. There are some really good people on this forum who know exactly what they're talking about, especially TxGreaseMonkey. Thanks again Tx. - Thop2010

Thank you for recognizing the effort that goes into this service!

Do Either Of You Have the Code List? I'm Getting Ten And Fourteen and I have no clue what those are.

10 IAT - Intake air temperature sensor

14 IACV - Idle air control valve

Mickey 83. Take it to Autozone or advanced, they will read the code free and tell you. Codes are different for different vehicles.

Since it's an OBD-I car, you can't use a code reader or scan tool. Instead, you must jump the Service Check Connector (SCC).