How to Check CEL Codes
 

When your check engine light turns on after the initial 2 second bulb check, it means the engine computer on your car detected a problem. The computer stores a specific code that will help narrow down your problem. The same goes for the D4 light (or S light) flashing for the transmission computer.

This site has some useful information about the CEL: tegger.com/hondafaq/faq_ii.html#errorcodes

All 96-present accords and the 95 V6 accords have a standardized OBD2 connector to get the engine and transmission codes. The 95 V6 and the 96-97 connector is behind the ash tray, while the 98+ are below the steering column. Most auto parts use a scanner to read the code(s) for free. Stop by, get the actual code, and post it on the forum. It will start with the letter P and have four numbers, like P1234.

NOTE: The 96/97 accords also have an OBD1 connector just like 94/95, so you follow the instructions below if your car can't make it to a parts store.

The 91-95 accords have a blue two-pin connector that you short with a piece of wire or a thin paperclip.

The 94-95 blue two pin connector is located under the glove box.

See: dhost.info/accordinfo/howto/cel.html

The 91-93 has the blue two-pin connector behind the passenger kick panel.

See: techauto.awardspace.com/dtc.html

In both cases you short the two pins on the connector using a thin paperclip or a piece of wire, then turn the key to the II position. Count the check engine light flashes for the engine computer (ECU). A long flash =10, short =1. So LLLLSS = engine code 42. You have to count the D4 (or S) light flashes to get codes from the transmission computer (TCU). Post the code and tell us if the check engine light or the D4 (or S) light flashed the code, because they use a different list of codes.

On 86 to 90 accords, you just turn the key to the II position and count the flashes on the LED of the ECU or TCU to get the engine and transmission codes like in the above paragraph.

The ECU is located under the driver's seat for the 86-89 accords. I am not sure where the TCU is located (or if they have one).

The 90 accord ECU and TCU is located under the carpet on the passenger side of the car near the firewall.

I could have made mistakes on this, so please post any information that is missing or needs to be clarified.

I've heard some places where car-parts-stores will not read OBD-2 error codes. Like California & some places in UK or Europe. Not sure if it's because of laws in those places, or whether lawyers are afraid of liability. But it's worth a few phone calls to find a place that WILL read the codes.

The whole OBD-2 thing is driven by a requirement by US-EPA. Many other countries in the world have it too, whether or not it's actually required. If someone from Europe, Asia, Middle-East or wherever wants to chime in, then we'll learn if OBD-2 is really world-wide.