Read Codes?

Jim,
When you turn the key on does the check engine light come on for 2 seconds then go out? If so that part of the system is operating correctly. Now do this. There is a blue connector all the way to the right under the glovebox. You may have to dig for it. It may be taped to other wires or tucked behind the plastic cover to the right of where your feet go. This connector has 2 wires in it and does not plug into anything. OK, key off at this point. Your need to make contact between the two wires so that they touch each other. There is special connector we use to plug into it that does the same thing but you have to improvise. OK, now turn the key on and read the code if there is one. Long blinks count as 10. Short blinks count as 1. Example: four long blinks=40. Three short blinks=3. Hence, code 43. Try it and give me a holler if your stuck or when you retrieve the code or codes. There may be more than one code. They just keep repeating so watch it a while to learn the pattern. i will try and be here for you.
Dave

I tried what you said. There is no code stored. Here is a summary of what happened. I hope you can advise me? I was driving the car home on Interstate 20 at 70 mph when it died instantly, as if someone flipped a switch. The tach went to zero. All other electrical worked properly. I coasted to a stop. Tried to restart the car. It would not. Was towed home. The check engine light was on as well as some (but not all) of the transmission indicator lights. Later I noted the fuel pump wasn't running. I removed the main FP relay and tested with an external 12v source and continuity with my multimeter. I'm positive both sides of the relay work. I tested the continuity of the FP wires. Good. I hooked up external 12v to the FP and it came on, but the car still wouldn't start. Then I removed the ECM from the footwell to get it out where I could test. I checked the 15A ECM fuse. Good. I checked for voltage at the ECM plug A26 and B2. Supposed to be less than 1V. There was nothing. Then I checked for voltage between A26 and A25 and also B1. There is supposed to be less than one volt. There was nothing. Then I tested for continuity of the wiring between A26 and B2 and the connector at the thermostat housing. It had good continuity (but don't understand why it would go to the thermostat housing - but that doesn't matter right now). Last I checked for continuity between A25/B1 and the fuel pump relay terminal. And it was also good. From all of this, it seems to me the awful conclusion must be the ECM must have failed. It is not turning on the fuel pump relay and it is not doing something else to let the car start. Would you agree ? Is there something else I'm missing ? Is there some other sensor that could be bad besides this ? I really appreciate your help. You can see I have some ability doing these things but am stumped. I don't want to have to find an ECM to buy and be wrong.

Jim,
Does the check engine light come on for 2 seconds then go out when the key is turned to the on position??? If so ECU is probably ok. You have checked a lot of things very well. Does the car have spark?? Pull a plug wire off the plug and stick a skinny screwdriver up into the plug wire so it touches the metal connector. Now hold the metal shank of the screwdriver about 1/8 of a inch away from a good ground and crank the engine to start. A spark should be visible jumping the gap. It is easier to see if it is a little dark. Two people makes it a lot easier. This year civic is known for failing coils and ignitors. Get back with me on your findings.
.
Dave

Dave, Thank you for your help and patience. I won't be able to test the spark until Sunday afternoon. I will get back to you then. I can tell you this: the check engine light comes on and stays on all the time, but I can't get it to read a code. We know the fuel pump will work, but it isn't coming on when the key is turned on. I replaced the coil about 4 to 5 months ago when it failed. But an aftermarket part, not genuine Honda. Maybe it failed again, or the igniter as you said? But that doesn't explain the fuel pump not working. I will test the spark on Sunday and retest all of the ECM readings again to be sure they are not working. Coming back to you then. Good thing I have another vehicle to drive (a brand new Ford F150).

Hi Jim,

If the CEL stays on and does not go off after 2 seconds at initial ignition switch ON, it most probably is due to a fault in the PGM-FI main relay or the ECM. Hope you have not kept the SCS connector connected.

The main relay is known to intermittently fail and when testing, it might show you the correct reading. Did you visually check the relay circuit board for cold solders?

If the main relay is ok, remove the ECM and check for corrosion and leakages of capacitors on the circuit board.

Before doing all these, check the ECM ground at the thermostat housing, remove, clean and reinstall

Had I opened the ECM and looked inside before doing all of the other testing and asking the questions, it would have been obvious. The circuit board is melted where one of the components is burned. I don't know what it is, a small cylindrical thing. Quite obvious and smelly. So, my final question is: I have a 37820-P06-A50 ECM. Can I use a 37820-P06-A52 ECM in lieu of what I have ? That's what I have found for sale ? Thanks for your help.

Hi Jim,

ECM are not interchangeable and if you use a different P/N, it can run but it could possibly show some other codes. I do not know the difference between the two ECM.

Why don't you try repairing the ECM? The cylindrical item you mentioned should be a capacitor and it would not cost you much to replace it. The part should be easily obtained at your local electronic parts store.

Jim,

You can use any P06 A/T ECM. That ECU that you found for sale is a M/T.

Basically, you have to make sure that P06-A50 this number is on the ECM that you purchase. It may be hard to find a P06 ECU that is A/T, however, many ECM tuners can chip and socket the M/T ECU to be made into an A/T ECU, this should cost around $40 because it is very easy to do.

Also note that any 92-95 OBDI P06 A/T will work, it doesn't have to be your particular year.

I was hoping I could repair the capacitor on the circuit board I have. But when the capacitor burned it - it really burned out. Because it also melted the circuit board too, about the width of a quarter all around it, even some of the outer metal cover. So that's out of consideration. The wrecking yard replacements I found were A51 and A52 ECM's (remember mine is an A50)and all claimed to be for automatic transmissions. They are out of a DX, where mine is an LX, but that shouldn't matter. The manual transmission ECMs were other numbers, not A50, A51, A52 (again so they claimed). The A52 are in the $45 to $60 range. So, I guess that's what a have to do, only if they guarantee to be compatable to an A50. I'm waiting to hear from the seller. I did find an A50 for sale. But $120. So, forget that.

Too bad the circuit board is beyond repairs. So only way is plug the purchased ECM and test. However ECM do not burn that way unless some shorting had caused it, so you need to be sure there are no shorted wires or components.

To test for shorting would not be and easy task as we do not know the cause of the burning unless there is some codes stored.

jimf1673,

I am sorry, but I have mis-informed you. I did a bit of research and I was mistaken.

a01 a02 are manual codes and a50-52 are AT codes. So yes! That p06-A52 will function properly in your vehicle! Purchase it and let us know the outcome!

Also, that is great advice from KHLow2008, please check for shorting circuits.

This finally wraps it all up.
I received the P06-A52 ECM I bought on Ebay from a wrecking yard in St. Louis.
Then I spent hours checking the wiring for shorts, continuity, voltage. I couldn't find anything wrong. I did learn that the wiring diagrams for the connectors are a little confusing: I thought the views were from the front of the connectors (looking in to the holes), whereas they are from the rear, where the wires are, looking towards where it would plug in to the ECM --(Duh !!). Makes a slight difference.
So, finally, I gave up. I did all of these checks because I was afraid the new ECM would instantly burn out too.
I plugged in the new (used) ECM. The car started in one-half second and works perfectly.
Case closed. Once again, thanks for all your advice.
Jim F. Fort Worth TX

Glad we could assist you Jim! Hopefully you have no further problems.

So replacing the ECU actually fixed the problem. Interesting I changed the computer two times and nothing.Now I have to replace it for a third time to see if it works. I doubt I will hear anthing from Jim F. Fort Worth, TX. However it would be great to meet him because I am in Fort Worth too.

It could be the distributor causing the problem. I have seen big problems with those more than ECM's for sure.

Remove the distributor cap and see if there is rust colored dust in there. This is a sign the unit is bad and needs to be replaced.

Please let us know what happens.

Cheers, Ken

which connector will i use? the 2 pin with 2 wires or 3 pin with only 2 wires?

here is a picture to get the codes.

Computer problem
1992 Honda Civic 4 cyl Manual 140000 miles

car quit running cheked with scanner and got no signal from computer replaced computer car run good about half day and guit again this time i see smoke come from computer and could smell it can not find out why computer got short or overloaded something is causing computer problem but what no wires burnt or hot anywhere don

Hi there,

you will have to start and back prob every wire and check for any short to ground, also have a look along the loom as you may see where it may be rubbed through, this is a very time consuming job, but it will be the only way to ensure that you find the problem.

Mark (mhpautos)

I changed the (Ecm or Ecu) and now have an engine light that still is reading code 9. And after I put a new Distributor on it was giving me the same code.

Tell us the meaning of code 9 please

Code 9 - CYP Sensor (Distributor Assembly) it's inside the Distributor.

CYP - Cylinder Position Sensor

It could be a number of things. Since you already replaced the distributor and the problem exists, check the following:

Distributor cap
Rotor
Ignition wires (make sure there are no electrical leaks) easiest to do in the dark.
With a timing light, check ignition timing to make sure it is correct and didn't jump time
If everything checks okay, it sounds like the CYP sensor is bad even in the new part.
Let me know what you find.