DIY : CHECK ECU for j00 !

[bennjamin]

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!

Hi guys ! Car running not-so-hot ? Most of our cars being Electronically-fuel-injected...any problem that can happen to our vehicles is usually derived from a malfunctioning sensor SOMEWHERE along the line.
So...here is a normally sure-fire way to quickly test your cars ECU , for any ECU codes which can tell of problem areas.


Aim: Here is a normally sure-fire way to quickly test your cars ECU , for any ECU codes which can tell of problem areas - of which is quick , easy and inexpensive which anyone here can do

Required: Yourself...and a small paper clip or similar object - such as a length of audio wire , tweezers etc.


As shown , I have choosen to use a paper clip stretched around to make a nice lil connecting handle of sorts.

Steps:
First , produce the DIY connector pin.
Next , place keys into your ignition , turned completley OFF.

Locate the 2 wire connector , located in the left-hand-side , inbetween the ECU location , and the bottom-left lip of the glove compartment.


Pull yourself underneath this are as it will be alittle hard to locate - look for a large bright green *shown* connector holder - and pull out the connector with the 2 wires , one been brown , and the other is green and white.


Next , place the DIY clip-connector into the 2 small bottom holes of the connector - completing the circuit and enabling the ECU's scan mode.


Finally...places your hands upon the ignition key- turn to ON *not start* - as you usually do to enable the fuel pump etc.

The engine check light should now come on either numerous times , or hopefully not at all - signifying one or more ECU codes that your engine is currently experiencing...letting you source the problem and replace say a sensor before it costs u alot of $$$

To READ the codes , observe the amount of "blips" and type - for example , a code 6 *ECT* would be like - "...blip...blip...blip..blip...blip...blip...S TOP" *repeat*


A code 23 would be ofcourse 2 long blips followed by 3 single blips in a row , then a short pause before repeating OR throwing another code.

IT is perfectly possible to have multiple codes - for example - code 3 + code 17 + code 6....would be represented by 3 blips *PAUSE* then 1 long blip then 7 short blips *PAUSE* then another 6 short blips. *repeat*


Other comments
Below , is the basic codes relative to MY civic - and pretty much most hondas from 92-00.

If in doubt...take it to a mechanic !

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4

[wynode]

Great work ben!

[bigteethygrin]

if your warning lights havent come on and ya cars still running crap then the ecu wont have any errors logged and so I think would likely show you nothing.

[ECU-MAN]

great work Ben. this should be checked every service. not only for the PGMFI health but more so to see if any codes apear in the SRS, 4WS, ABS systems.

[wynode]

if your warning lights havent come on and ya cars still running crap then the ecu wont have any errors logged and so I think would likely show you nothing.

I've read that 3 times and i'm finding the comment very vague!?!

The above mentioned ECU does not 'log' any errors, but rather it is a self diagnostic mode used for......well diagnostics.

[bennjamin]

to add....most of these "diagnostic codes" are not known until you actually log onto the ECU via this DIY way or on a actual diagnostic tool.
More so the point of this - is to diagnose problem areas before they result in greater things i suppose.

[Javed]

My light seemed to stay lit whne I did this. Any ideas? DC4 teg

[bigteethygrin]

I've read that 3 times and i'm finding the comment very vague!?!

The above mentioned ECU does not 'log' any errors, but rather it is a self diagnostic mode used for......well diagnostics.

sorry to be vague..

I meant that a faulty sensor will throw an error on your ecu.. then you will see your warning lamp lite up.. once its lit then you can follow the above procedure to discover what is actually wrong with it. If the warning lamp isnt lit then the ecu has not detected any errors including sensor failures.

The procedure above doesnt actually force your ecu to run through a series of diagnostic tests but instead it makes your ecu display errors logged from detected sensor failure during operation. Or other failures for that matter.

I'm pretty sure this is how it works.. the procedure is great though!.. I have used it myself to diagnose my 4WS probs. The 4WS prob is an example of where the warning lamp was already lit and the procedure above was used to diagnose why it was lit.

Hence (provided all dash light bulbs are working) if you dont have a warning lamp already lit up on your dash then the procedure above wont really do anything for you.

[wynode]

Also remember, after fixing the source of the problem, you need to reset your ECU to loose the CEL code

[ECU-MAN]

My light seemed to stay lit whne I did this. Any ideas? DC4 teg

then there is no fault.

[Javed]

lol. seems odd, my car is using oil (probably leaking it somewhere) like a bitch.

[SiR JDM]

I think my engine check light has been cut (by the bastard mechanic >_< ) anyway, this wont work for me any other way if the engine check light is cut?