DIY PGMFI Diagnostics - Code 0 ECU

**ECU-MAN** · 19-05-2007 01:09 AM

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

Aim:

Diagnose code 0, ECU, the ECU "Electronic Control Unit" is also known as ECM "Electronic Control Module"

Required:

- 10mm 3/8 socket
- 3/8 extension bat
- 3/8 ratchet
- Philips head screwdriver
- another identical ECU

So when you start your car, Your engine light "MIL" comes on and stays on. You do the PGMFI test and you get a solid CEL. Chances are its the ECU at fault. Very rare but possible for a stock ECU, more common if you have been tinkering with ROM's ect.

Symptoms

- Engine light on all the time and the bellow symptoms
- Engine will not start.
- Engine starts but only revs to 3000 or 4000 rpm
- Engine idles higher when warm
- car runs like crap

STEP 1

Locate your ECU and remove it from the car. Your ECU could be located in a number of many possible locations. Commonly on the passengers side foot well kick panel or floor well, pull the carpet back and have a look.

..

- on the floor well it will have a big metal plate covering the ECU, undo the 4 nuts holding it down with a 10mm socket ( yellow arrows ) undo any cable ties connecting to the ECU ( red arrows )

- now unplug the ECU connectors ( right yellow arrow in bellow picture ) and unplug the AT ECU if applicable ( left yellow arrows ).

STEP 2

Use a Philips head screw driver and open the ECU covers to look for obvious damage.

- undo the screws holding both covers down, back and front. (Yellow arrows in bellow pic)

Have a look in the ECU for any obvious damage. Bellow is a good example of a burnt out ECU, you can see the big black area. This is not good. This would have been cause by some one very talented who would of hooked up the battery terminal back to front or some thing like that.

The above is an obvious failure. However if you open your ECU and you do not see anything like the above, then you can only check the ROM if in place firmly in the event that you have a modified ECU.

Locate the ROM and make sure it’s firmly inserted if it’s removable. Press down firmly in the centre of the ROM to seat it. See bellow pic yellow circle

At this time you should put your ECU back together, because unless you know what you’re doing you could create a fault if it doesn’t have one.

Substitute a known good ECU in your car and retest. If you have the same problem with a solid Cell, then your ECU is more than likely ok. If the substitute ECU starts and runs fine, your original ECU is toast.

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

No part of this DIY is to be reproduced with out acknowledgment of the site and author it came from, ie me and ozhonda.com. Do not rip parts off and claim them as your own.

**beeza** · 11-04-2008 12:31 PM

I'm getting a solid cell,it's staying solid.In the pic it's flicking off every 4-5 seconds.Is my code the same as this.Cheers John.

**ECU-MAN** · 11-04-2008 01:00 PM

yes solid cel can be considered as code 0 on a stock ECU ( ECU failure ).

is your ecu stock ???

**beeza** · 11-04-2008 03:05 PM

Yup.I've changed a bunch of things already...

**ECU-MAN** · 13-04-2008 05:48 PM

what car is this ecu from. year and tranny type ??

do you have an add on like rsm ect ??

**beeza** · 13-04-2008 07:46 PM

96EK1 Civic Gli d16y4 Automatic.I haven't modified the ECU at all but I have a resistor in the IAT sensor.It's the one that tells the computer the air temp is a couple of degrees lower and it compensates by giving a bit more fuel.I don't it relates but better to say now.
I opened the ECU up and there was no obvious damage.

**ECU-MAN** · 14-04-2008 01:57 PM

remove the resistor and put it back to stock and reset the ECU and test again.

**beeza** · 14-04-2008 02:19 PM

The problem is I've got a custom intake,so I haven't got the other half of the IAT sensor...

**ECU-MAN** · 14-04-2008 03:26 PM

what value is the resistor.

is the IACV connected

MAP and TPS connected.

although each device should give an individual code.

back to the begining thou, is the engine light on when you drive ???? with out the SCS bridged ???

**beeza** · 14-04-2008 03:55 PM

Yes the IACV,Map and TPS sensor are connected.The engine light dosen't come on when I drive only when I do the ECU check.
I'll have to get back to you with the value of the resistor.It's been in there for 2 1/2 years...

**JasonGilholme** · 14-04-2008 04:10 PM

beeza, more fuel is going to loose you power. unless your trying to cool your cylinder temperatures down, it'd be better off removing the resistor.

**beeza** · 14-04-2008 04:34 PM

I've been wanting to remove it for a while but I haven't got the other half of the sensor,the part that connects onto the intake arm.Am I able to just get another one,but I would have to connect it to the intake so it can get a reading wouldn't I?