bossportsman

Hey everyone,

I recently bought a 2003 civic sedan with a manual trans. It's a Canadian base model, I bought the car as a project from a friend who decided he didn't want spend the time to get it running. Any way I have done some research on the forum and it seems like the ECU may have failed. Here's the symptoms:

Non functioning tach and temp gauge

2000 rpm rev limit (limp mode?)

Key light flashing on dash

Check engine light

Port reader cannot connect to ECU to read code

So I'm wondering if anyone has any thoughts regarding these symptoms, I have read about alternator brackets causing a voltage spike to blow the ECU, how can I check for that? Plus is there a way to test the ECU?

Thanks in advance

ezone

You pretty much have it covered.

Word for word copy of Hondas service info: http://www.underhoodservice.com/issu...ontentid=88560

Fix the alternator problem first so you don't fry another PCM.

Be aware that bad engine grounds might cause it too. Ground strap from the body to the trans and another from the body to the top of the thermostat housing/water manifold. Rust and corrosion can take their toll.


HTH

bossportsman

Thanks for the reply ezone,

Whats the best way to go about correcting the alternator issue?

BTW I haven't really done much with the car other then scan it yet so can you tell me where the ecm is so i can get the part number off it?

Thanks again

ezone

Explained in that bulletin info linked earlier. Get a service manual if you can't figure it out from that.Much simpler to just enter your VIN into a parts catalog and let it pick the right part number.


It only matters what market the car was built to be sold in. In the US we have plenty of cars built in Canada.

You are LOCATED in Canada? Try the toronto honda parts site. http://torontohondaparts.com/OrderParts.aspx

In the USA I use
http://www.hondaautomotiveparts.com/






PCM is behind the glovebox.

If it is truly bad and you replace it, you will probably tow it to a dealer to get the immobilizer programmed. Take all your keys.

bossportsman

I am in Canada. I picked up a used ECM for $100 with a 90 day warranty today. I'm planning to get the car inside this weekend to check over the alternator, grounds ect. Then ill pop in the new ECU and get to the local dealer for the reflash. Ill post an update after that.

Thanks again ezone

ezone

YW.

Just remember, if you don't solve the original problem you will only burn up the new PCM.


Assuming the diag was right in the first place.

bossportsman

Hey Ezone,

I tested the alternator and it doesnt seem to be working. I charged the battery just to make sure all was well there. It was putting out 12.4v with the key off. At idle the voltage was still 12.4 and seemed to drop by .01v every minute or two.

The bolts in the alternator were tight.

The alternator fuse under the dash was good.

Any thoughts? Is it possible the alternator failed and therefore fried the ecu?

Thanks Again

howie2011

I'm pretty much having the same problem. Tach/heat gauge/ high rev/ battery light. Where can I get a cheap ECU cause I don't have the $420 Honda wants for it

ezone

So it isn't charging.

How about the other problems? Communication? CEL? Green key light? Poor running?
Still has all the same problems as before, now that the alt mountings have been corrected?

Wait a sec...You bought the car in a state of broken. You don't KNOW what happened, the cause or what work was already done.....Previous owner could have corrected the alt problem then figured out the PCM would be expensive and dumped the car.
Your alternator COULD be perfectly good.
The voltage regulator is controlled by the PCM.
If the PCM is actually bad, that can certainly keep the alternator from charging.

Anything that causes the alternator to overcharge can fry the PCM. The common cause is the loose mounting bolts as outlined in the bulletin linked earlier, but could also be other poor/bad grounds for block/trans/chassis as I said earlier.
My understanding is somewhere over 16-18v starts damaging the 12v electronics....Even a battery charger/booster could cause damage.

ezone

That's pretty damn cheap for factory parts. Better jump on that if it includes the programming and installation. (Majestic shows $462 for a 03 EX auto sedan PCM.)


No matter where you find a cheap PCM, you probably pay for a tow truck and programming at the dealer before the car will run.

Local junkyards,
www.car-part.com
You better know exactly what part number your car needs though.

bossportsman

So what do you recommend my next action be? How can I determine if the alternator is functioning correctly?

ezone

You are trying to see if it will charge while it is on the car, your alternator is not going to be able to charge until the PCM problem is corrected. (The PCM controls charging, and the PCM is broken, remember?)
You could take the alternator off the car and carry it into ChinaZone and have them bench test it.


------------------------------------

If it were me....

Running on the assumption that the PCM is already known to truly be failed, then I'd make my next assumption:
If the car has less than 200,000 miles on it, I'd be inclined to think the original alternator is probably OK, at least for the moment.

If I was concerned about it, I might unplug the wire connector from the alternator so it cannot charge at all....
Then replace the PCM.
Program the PCM and immobilizer.
If the engine runs correctly now, that proves the PCM was bad.
Now reconnect the alternator and run the engine, while monitoring system voltage.
Is it operating/charging normally now? (Probably.)
-----------

Why I think your alternator is probably still ok:

Overcharging is what burns out the PCM, according to the service info bulletin.
Overcharging is not the usual failure result when the alternator itself goes bad.
Weak or no charging is the usual result of an alternator failure.

Overcharging is usually the result of human errors (at least on these cars it is).


Plus, the alts are pretty reliable overall.

--------------------

Did any of that make sense?

bossportsman

That makes perfect sense to me. Bypass the alternator altogether untill I get the PCM changed and am certain it was the problem.

Ok so next question, is the tool used to flash the PCM only availible at a honda dealer or can it be done with another brand of tool (snap-on ect.)? The reason I ask is that I have a friend who is a mechanic that would come right to my house to flash it but he has to look into wether or not his tool will work. Is it worth his time or is this service only availible at a honda dealership?

Thanks

ezone

I can't answer about aftermarket scanners, but I seriously expect they cannot do it.


Dealer level (older style) PGM tester and all the immobilizer codes, or the newer HDS scanner with security access for programming immobilizer keys is what you need.

Dealer, unless you have a true Honda specialist local to you.

MAYBE a super well equipped locksmith that has heavily invested in the necessary tooling to program Honda/Acura Immobilizer systems. Are you in a big city?
Around my town, nobody but the dealer can do it.
Local locksmith can program keys for "the big 3", but "none of them furrin cars".

howie2011

No matter where you find a cheap PCM, you probably pay for a tow truck and programming at the dealer before the car will run.

Local junkyards,
www.car-part.com
You better know exactly what part number your car needs though.[/QUOTE]


It doesn't include programming or installation. And how do I know which part number I need

ezone

Use one of the many online Honda parts catalogs.

Use a catalog for the country you are in.

http://estore.honda.com/ (US)
http://www.hondaautomotiveparts.com/ (US)
http://torontohondaparts.com/ (CAN)

Enter your VIN so the catalog can narrow the choices for you.

Without entering the VIN of your car, there might be 2 dozen choices of PCMs to sift through. Pick the wrong one and you waste $700 or whatever.

HTH

bossportsman

Hey Ezone,

I finally got my salvage ecu flashed. The car runs well now but the battery light is on at idle. If I rev the car over 1000 rpm the light goes out. I checked on the battery posts with a volt meter and the alternator appears to be NOT functioning. The voltage sits around 11.6 volts at all rpms. The voltage is also 11.6 when the car isn't running.

So the question is, is the alternator the obvious issue or is there something else that could cause this symptom?

Thanks again

ezone

Should I assume then that if you rev the engine up above 1000 RPM that the light goes out, and it does charge and put out 13+ volts?


If the bolts are tight, and you don't have any "power pulleys" or a loose belt, then I'd probably suspect the alternator is weak or bad.


Does it howl loudly?
Got a way to load test it?
If you smack it with a hammer, does it work again? (kinda LOL, kinda serious)

bossportsman

It doesn't seem to ever charge so it seems odd that the light would go out over 1000 rpm. I can read voltage across the battery and rev the car and it never goes over 11.6 volts.

And it doesn't make any funny sounds. I can take it to an alternator/starter shop in town to have it tested.

ezone

Check all fuses. Fuse 4 in the dash box
Check wiring at the alt, the big cable and the blk/yel wires must have battery voltage when the key is on
The other 3 wires go to the PCM, see a service manual for testing. PCM controls the voltage regulator, field, and the idiot light on the dash.




I was figuring it was charging when the light went out. Oh well.


Does the new PCM have an exactly identical part number as the old one?

crazyo

used a drill and wire wheel cleaned all the brackets for the altenater the i pull the 80 amp fuse under the hood looked ok but it was split in two thats the battery fuse doesnt get contact when you hit the gas drops into limp mode so got a new fuse cleaned all grounds car runs like a champ i bought a new ecu for nothing

crazyo

used a drill and wire wheel cleaned all the brackets for the altenater the i pull the 80 amp fuse under the hood looked ok but it was split in two thats the battery fuse doesnt get contact when you hit the gas drops into limp mode so got a new fuse cleaned all grounds car runs like a champ i bought a new ecu for nothing

Myhondaisbroken

My car is having the exact same issues as Boss's, although it's an EX Coupe. What was the ending solution to this?

crazyo

My car is still going with 265,000 miles like i said clean all brackets with wire wheel check that fuse under hood if its bucking and going into limp mode check the seal on the valve cover oil drips down into sparkplug hole and causes misfire to cook ecu ifixed a few of these

crazyo

you can flash your own now google it for your honda 99 bucks

Jessica B

That sounds exactly what is going i with my car. I have a valve cover leak. The shop cleaned under the car and asked me to bring it back after 2 days. It broke down before the 2 days (I'd known about the issue a bit before, they'd cleaned it once already and I'd gotten busy.) Lesson learned! Thank you for your reply. It helps me feel confident to replace the Ecu, then the valve cover leak.