Honda Civic / Del Sol (1992 - 2000) EG/EH/EJ/EK/EM1 Discussion

Help: ECU Problem. Scan tool won't connect / read P72 ECU

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Old Jan 26, 2009 | 10:26 AM
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Default Help: ECU Problem. Scan tool won't connect / read P72 ECU

Alright, it looks like after my last problems with this car, I decided to get a motor swap and all is running smoothe. I have a 97 EK sedan with a GSR swap, and I went to get the emissions tested twice on Saturday, then once earlier today and I am getting the same problem. Their scan tools cannot read my ECU. Basically, they are saying that my ECU is unable to connect. My car runs perfect, however, sometimes it does have trouble starting up in cold mournings as it takes me two tries to start my car.

Does anyone have any input on what could be wrong? I am guessing it is the ECU, so I am gonna have my co worker swap his ECU into mine. I have a P72 ECU by the way...

Please, any help is appreciated, thank you.

Update: I just got off the phone with the shop who did my swap. I had no clue what he was saying. My car does have a knock sensor on it and I thought OBD2 motors have a knock sensor? He said something about me having an OBD1 ECU and my car is an OBD2A so I have no idea what to do. Have any of you run into this problem?

Last edited by Agent_EM1; Jan 26, 2009 at 11:56 AM.
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Old Jan 26, 2009 | 10:46 AM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

ANyone?
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Old Jan 26, 2009 | 11:24 AM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

Im not 100% sure but depending on what motor you use, an OBD1 motor will cause the DLC not to work anymore. OBD2 with the right harness and ECU, should be able to use the DLC....Correct me if im wrong.
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Old Jan 26, 2009 | 11:55 AM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

Thank you. Yeah, I just got off the phone with the shop who did my swap. I had no clue what he was saying. My car does have a knock sensor on it and I thought OBD2 motors have a knock sensor? He said something about me having an OBD1 ECU and my car is an OBD2A so I have no idea what to do. Have any of you run into this problem?
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Old Jan 26, 2009 | 12:47 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

up
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Old Jan 26, 2009 | 02:37 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

Originally Posted by Agent_EM1
Thank you. Yeah, I just got off the phone with the shop who did my swap. I had no clue what he was saying. My car does have a knock sensor on it and I thought OBD2 motors have a knock sensor? He said something about me having an OBD1 ECU and my car is an OBD2A so I have no idea what to do. Have any of you run into this problem?
You need to find an OBD2A USDM GSR ECU. It will be plug and play. Oh and you may need to do this to get rid of the CEL that will appear:

http://technet.ff-squad.com/ckftrick.htm

Then you will be able to scan the ECU through the data link connector. JDM and OBD1 ECUs will not read through the data link connector.
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Old Jan 26, 2009 | 04:31 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

If its a JDM OBD2 ECU it wont communicate with the scan tool, if its any OBD1 ECU it wont communicate with the scan tool. As already stated you need a USDM OBD2 P72 pulled from a '96 - '99 Integra.
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Old Jan 26, 2009 | 04:52 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

Yeah, I talked to him again and it looks like the owner is gonna work on my car on Wednesday. He's gonna do all the labor for free as he gave me an OBD1 motor. He's gonna convert the ecu harness to OBD2 for a P72.
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Old Jan 26, 2009 | 04:55 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

noice at least you got that **** fixed for free
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Old Jan 26, 2009 | 05:23 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

yeah good thing they are fixing it for free but my qestion is why whould they do it the wrong way the frist time then half to fix it again somethig aint wright their.......
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Old Jan 26, 2009 | 06:51 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

i think the reason why there is a obd1 ecu in your car is so that the cel for your knock sensor wont come on, i dont know if you have one or not. but if your running a obd1 ecu it cannot read and link with the scan tool. i have the same problem because im running a mini me on my ek hatch and running a obd1 p28 ecu instead of a p2p. i ran it because i didnt have a knock sensor hook up and my secondary o2, so the obd1 wont recognise it not hooking up... but thats just my problem i dont know if this will help...
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Old Jan 27, 2009 | 02:24 PM
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Default Re: Help: ECU Problem. Scan tool won't connect / read P72 ECU

What i'm wondering is, can you just tell the SMOG or Emissions people to test your car the OBD1 way? Haha... ANyone else?
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