ECU Tuning & Fuel Management - check engine light! Help!

Ok so I was driving my 99 civic lx(at) today when my stereo suddenly started to turn off and on so i took it off. Then my lights were dim andmy speedometer didn't change its position. Trying to drive it felt as if the ebrake was on it was driving very laggy. My friend said thats it my alternator. What do you guys think it is? I have a indiglo gaugues that I hope is not the reason this happened. Thanks in advance.

Check fuse #15 (7.5A) in your under-dash fuse relay box (see picture). It may have blown.

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The title of your post also indicates that your CEL is ON. Have you tried to retrieve the code?

I tried changing the fuse and the stereo now stays on and the car drives regular so it seems but the check engine light is still on and the lights are dim. So I don't know what else to do. Im scared to keep starting it up because it seems to struggle to start, the lights get real dim.

Did you find a blown fuse?

The picture shows how to retrieve the CEL code. The Service Connector (2P) is located behind the front passenger kick panel below and to the right of the glove box. The Service Connector is packaged into a blue/green rubber holder and branches from the main ECU wire harness. With the ignition OFF, use a wire to connect the two terminals of the service connector, and then turn the ignition switch to ON. The CEL will blink the code as described here:

http://www.c-speedracing.com/faq/06.php

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Next, clear the CEL code from the ECU (see picture in next post). Run your car and see if CEL turns ON again. If so, retrieve code again and verify that it is same one as the first code you retrieved. Repairs will be guided by the CEL code(s) that you retrieve.

If the CEL does not turn ON and you still have electrical problems, you should test the battery and alternator.

Last picture...

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OK i got the cel code and it was 7 long so i guess thats 70 but then I reset it by pulling the back up fuse and when i put the ign switch to on the check engine light did not flash it jus stood on. and now the car doesnt start at all. So the code number is 70 o believe which means "Automatic Transmission malfunction with the automatic transmission controls." I donno any more because the last times i drove it it seemed fine transmission wise. I donno what to do I was going to take it to Honda service tom but now it doesn't start so I donno what to do.

Sorry you are still having problems. I have a few questions:

1) Did code "70" repeat again after the first time? If other codes are stored in the ECU, the other codes will follow, so you need to wait for the blinking pattern to repeat itself. I agree that code 70 is rather unexpected.

2) After retrieving the code by the "jumper wire" method, did you turn the ignition OFF, remove the jumper wire, pull the BACKUP fuse for 10 seconds, return it to the correct slot, and then turn the ignition key to ON. With the code is cleared this way, the CEL should turn ON for a few seconds and then turn OFF.

3) Your car may be unable to start because the battery is now run down. Try to recharge it or get a jump start.

4) Was fuse #15 blown when you first checked? If so, recheck it again. Also, double check that the BACKUP fuse is not blown.

Start the car, let it run. Get a Volt meter and see if the car is producing 14.4 volts. If its not, then your alternator is shot.

Sorry you are still having problems. I have a few questions:

1) I got 7 long blinks then a pause then 7 more long and kept repeating.

2) This i did not do. I left the jumper wire in there then pulled fuse then turned ign on. then the cel stood on so i tryed to turn on car with the jumper wire still on so maybe thats why it dont wanna start now donno.

3)hope i can jump start so i can just take it for service

4) I didnt really check I just replaced it

Try this:

1) Turn ignition to OFF. Remove the jumper wire. Turn the ignition to ON (without starting car), and now the CEL should light for a few seconds and then turn OFF. If so, move to next step.

2) Now try to start the car. If it starts, keep it running in an attempt to charge your battery.

3) Pete may be correct that your alternator is bad; however, first rule out more simple problems, such as a weak battery and potentially corroded battery terminals. Get your battery charged, if necessary, and clean the battery terminals to ensure good electrical contact.

hmmm well I will try tom morning but last week when honda changed my oil they checked battery and said its good so maybe that solves that. but if its the alternator theres no way to start it to drive it 2 miles right? I might have to tow it :( and about that CEL i hope it aint the tranny

A blown fuse #15 would affect proper alternator function and potentially lead to discharging of the battery. As I believe that you mentioned noting some improvement after replacing fuse #15, then this is real possibility. Also, assuming a faulty alternator (which I am unsure about), it may still provide sufficient charge to drive the car (turn all accessories off). Good luck.

Also, regarding the tranny code, did you notice whether the D4 light in the gauge panel was blinking, in addition to CEL being ON?

If its only two miles you could try to charge the battery by hooking jumper cables up to a running car for a hour or so..............then you should be able to go a few miles.

yeah the d4 was actually blinking as well I didnt pay attention to the length of time it was though. Well the first time this all happened I parked car and left it for awhile then I switched fuse and started to park it in my garage and the tranny seemed fine no lag no holding me back or anything but the lights were still dim.

The blinking D4 light and the CEL code are both signaling a tranny problem. Your dim lights are a separate problem, likely either your battery, cables, or alternator.

Can I assume that after you changed fuse #15, your speedometer problem resolved?

$hit! not the tranny........... and about the speedometer I completely forgot to look at that hopefully my car will start tom and i will check but I am so pissed off because all this happened out of nowhere

Considering that you haven't noticed any functional problems with the tranny, the CEL and D4 codes hopefully signify a less worrisome electrical problem. Anyway, good luck with the repairs.

thank for all quick responses and now that i think of it i hope the auto start doesnt have nothing to do with it cause i heard alot of complains abut those things

nope doesnt start :( and its making a cranking noise and with my luck its raining in my part of town.