mdl-04ex

Okay, today I was driving and the car stalled. I restarted it... It did not have any readings in the rpms or coolant temp. Car wouldn't rev over 2k? Just a guess since it wouldnt read any Rpm. Also check engine light and the green key are both on. Car idles fine but won't drive over 2kish n each gear.

Also a scanner did not read any codes.... Any help would be great. Ty

It Wasn't Me

Try resetting the ECU. Disconnect the battery, or remove fuse #6 from the fuse box under the hood. Wait a minute before you reinstall (or reconnect) it.

mdl-04ex

Well, we tested every fuse and all the wires that come from the ecm everything was fine, But it wont connect to the ecm... We checked the harness for any corroded wires or anything like that. Everything seemed fine, We pulled the battery cables off the battery and touched them together.

I orderd a ecm, Im just hoping thats the problem....

It Wasn't Me

Hmm... well, good luck with it. There has been other people with a "failure to communicate with the ECU" problem, and replacing the ECU didn't help.

mdl-04ex

Well, Somebody has to have figured it out. The bad part for me. Is i missed 1.5 weeks of work because im a single father and my job requires driving and I have ran out of options.

I bought the new ECM and went to the dealer in limp mode. They installed it...And once they installed it it was throwing a bad "heater sensor code" I believe that he said which is the 02 sensor. Not sure though... So I was driving home (Happy, glad... thinking finally!) i get about 10 miles down the road... the car Jerks and stalls out on me...i restart it up... the alternator belt is screaming bloody murder... and it was showing a batterylight.. and check engine,car was not in limp mode (yet) so im on the side of a small highway and i start it up and drive it off to a near parking lot... which was hard to do... and stomach turning...

Then my check engine light is flashing and everytime it flashed my ECM made a click and the car would jerk and all of a sudden loose power when it would flash for a quick second. My buddys shop was not to far, and he reminded me the alternator belt is not connected to water pump so u should be ok. So I get there and it went back into limp mode.. :/ Grr.. so now I find out the ecm isnt for a ex vtec... but it ran fine while it did...so now the ecm is back in limp mode... no tach or temp guage...im so lost.... I ordered a the RIGHT ecm this time not from someone on ebay who thinks any 04 ecm will work. and a new alternator... Im just worried it is more then that..

I believe it maybe be the 02 sensor (can that even cuz such a problem)??

Or a bad ground????

Please if anyone has anything that can help. I am more then grateful to take any advice thrown at me.

Thanks!

mdl-04ex

Bump~ anyone??

JCRasta

iTrader: (1)

Same thing is happening to me right now but it won't go pass 3500 rpm. Ran the codes came out with 8 misfire in all 4 cylinders u2 sensor codes and camshaft positioning señor a bank 1 malfunction and camshaft position sensor bank 1 ckt intermittent. I reset the codes then the two camshaft codes came back and won't go away. Still stuck at 3500 rpms. Anyone know?

thatmexican32

yeah so the same thing happen to me sometimes ever since i did my 5 speed swap.it goes away when my battery and check engine light are both on and it happens one day and the next day its fine.both my rpms and temp gauge dont work ether during the problem.i changed the o2 sensors and checked all the grounds in my car so idk if that could be the problem.hope someone has a answer to this.

civichxtreme2

I had the same thing happen on an 01 a while back and it was a heavily clogged catalytic converter, just a thought

JCRasta

iTrader: (1)

Changed my cps sensor 2 hrs later and all was good.

mdl-04ex

We must have a different problem, Because mine doesnt even connect to a obdII scanner, Tried 4 different ones. The computer is being fried by something...I have been through 2 ecms now... But I seriously have no idea what is causing it... neither does any mechanics... Im now 2.5 weeks without work and no funds for a new car... im losing hope at this point.

civichxtreme2

Ok try this if you can. Disconnect your exhaust system from the bottom of the manifold, just simply disconnect it, start it up, while it may run loud, it may run fine, the damn 7th gen Catalytic converters are garbage and tend to clog up really easy.

mdl-04ex

I know why it wont connect. It wont connect because the ECM is fried. I been through 2 now reseting it doesnt do anything if its fried it is at the point of no return.

So I changed the alternator cuz it looked like crap and the second time my pc was fried it wasnt right away just after the alternator kept locking up and the belt was screaming... and it would jerk like the belt was locking up. So thats changed now the belt doesnt squeel even in limp mode. So that might have been the problem... I will update if i figure it out... But like i said it was throwing p0141 which is secondary 02 sensor... so idk if that will link to it or not i havent tested it yet

mdl-04ex

PROBLEM SOLVED.


Alright guys, after 3 weeks of research and testing. I have figured out why this has happend.

Its not a problem anyone I know has ever seen or delt with, My father owns his own shop, and a close friend owns his own shop. neither one could figure out why it was in limp mode and what caused it.

3 weeks, 3 ecus, 1 alternator later. The car is fixed.

With these civics, The alternator mount is what grounds the alternator. If the bolts are not bolted down tight (suggest torq specs). The alternator will spike voltage right to your ecu and kill it instantly. So you can either have a bad alternator that is arching, or a alternator that isnt tightly bolted on or has some corrosion on the bolts/mount which will cause it to not properly ground out.

My symptoms were: no temp gauge reading or RPMS. And a OBII scanner will have no communication. will idle like crap when first started then act normal. But wont rev high at all, in each gear it will probly go up to 2k rpms.


My suggestions to fix this problem if it is the same:

1. Have your alternator tested. check to see if it has any rust or bearing noise, If so I would suggest getting a new one.
* When you install the new/current alternator back into the vehicle make sure its on nice and tight.

2. Find your exact ecu number from a junk yard/Ebay. (you will save yourself about $800.00.
*This is critical, Has to be exact numbers (Because there is only 1 or 2 differnt ending numbers that will fit each car, So just find the same ecm part numbers to be sure you have the right one).

3. Go to the dealership. Tell them you need your used ECM (They will call it a PCM). But tell them you need them to rewrite the vin number and reflash it to your keys/car.
(Trust me, They will get you for labor if you are not clear with them, Because they will do the reflash and not change the vin and probly charge you an extra hour cause they will then realize they need to re-write the vin number).

I hope this helps, There isnt really anything else that will kill a ECM and have it in limp mode with no communication.

It Wasn't Me

Glad you got it sorted out! Thanks for the update, too. I'm certain your post will be helpful to many people.

flyfast727

I have a 2005 Civic HX with MT and have been searching for about 2 weeks now. I had a very similar problem. My alternator adjust bolt came out (missing) , belt started squeeling. Installed new belt/bolt and came up with all kinds of other problems ...batt light coming on with RPM cycling every 10-20 secs with the main relay cycling and the CEL cycling with every click of the relay and after about 3 mins, batt light goes out, CEL comes on steady RPM's go to 0, temp guage dies, A/C comp stops working, won't go over 3500 RPM, max 65MPH above that engine cuts abruptly.

1. Replaced Alternator- NO HELP (that one had 235000 miles on it and was weak on the load test.

2. Dug around on forums for hours on end.

3.After it goes into limp mode. Scanner says link error.

4. Checked and cleaned every ground. G101, G201, G301, G451 etc....

5. took it to dealer and they wanted troubleshooting fee of $140 and they came back after 2 hours and wanted to authorize more troubleshooting time.Ed Morse Honda in Riviera Beach, Fl (figured I could just buy all new parts by the time they get through telling me what was wrong with it)

6. rang out wires in engine harness thanks to HELM manual. Found no shorts.

7. Beat head against wall repeatedly.

8. Dug around on forums again and found this thread. Ordering a new ECU from Majestic Honda tonight. $365. Hope this helps. Dealer will be happy to see me again to reprogram it. ARRGGG!!!

Will let you know how it goes.

jheyde

I had the same thing happen to me just recently, same as mdl-04ex.
I purchased a used ECM thru ebay, but the dealer say's the can't program it without the original VIN from the car that the ECM came out of? Does this make any sense to anyone? I have the exact same thing: No tach, no temp, limp mode. Mine was because I forgot to tighten alternator bolt after doing the timing belt, water pump, etc. It arched to the block and now my code scanner won't read. Car starts, gauges work for a split second and then die. Makes me wonder if it's a relay?

jheyde

And has anyone heard of that? Not being able to reprogram a used ECU because I don't have the original VIN from the donor car? I haven't read that anywhere....and the dealer got me fro $60+ diagnostic

blue demon87

I have a 02 it did the same thing u need to change ur cps is u need help i can tell u how to do it just email me at catriphase@gmail.com

Djratrap

I had a similar problem with arcing that fried my ECU. I was running a catless header (megan garbage) on my d17a1 the header pushed out the secondary sensory and bent the wires causing it to ground and blow a fuse. This arc was also enough to fry my ECU. It was just a matter of time before i started noticing problems when going back to the stock manifold. I would get random shorts and my ECU would throw out random codes. As well as only randomly working with my obd2 reader. My car also went into limp mode randomly and got stuck it in. 4 tows and a new ecu later my car was good as new. Moral of story. Megan is garbage. Also, if running and aftermarket header make sure the secondary O2 sensor is not pushed up against anything.

blue demon87

I had the same promblem and it was my cps it not that hard to replace and i can let u kno how to do it

Cain1977

What is a CPS? I have a similar problem.