How to pull engine codes off the ECU?

[Toahk]

Well I have called around, and the cheapest place that they will run a diagnostic on my car is 60 something dollars. Ive heard you can actually pull codes off your car without any special equipment, would someone tell me how? Im just wanting to because I have a 6 hour drive in a few weeks and the check engine light has been on for a while. Thanks in advance

[Nismo_Freak]

ECU is located in the right side passanger's kick panel.

Pull it out (2 or 3 bolts (10mm) IIRC).

Find the screw on the ECU (flat head screw), should be on the side.

Turn ignition to ON position

Now, turn the screw clockwise until it stops (DO NOT FORCE IT!), it should be circa ~ 1.5 rotations.

Count to 5

Turn screw back to original position.

The MIL (Check Engine Light) should be flashing.

Here's how you read the code. - Count the number of LONG flashes - Count the number of following SHORT flashes- MIL will pause, it will then repeat the 1st code or give you another diagnostic code.

The LONG flashes give you the digit in TENS The SHORT flashes give you the second digits

If you are 93-94 model:1 Long and 3 short would equate to a No. 13 error code

If you are 95+ model:1 Long and 3 short would equate to a P0103 error code

If you have an Autozone in your area you can go there and they can use an OBDII scan tool if you have a 95+ model car, they do this free of charge.

[Toahk]

My car is an 89, and iirc they use OBDI. Thanks for the show-me-how. Its gonna save me 60 some odd bucks!

[Nismo_Freak]

Hmm... I'm not 100% sure it will work on 89-90 OBDI but you can always try!

Also, tell us what your experiencing in terms of malfunction on the car. Does it have a miss, hole in the powerband, strange noise, not running 100%, etc. When does it happen.

[Toahk]

Nothing is lacking at all, but the check engine light is on. There is a red and green light on the ecu, I read up on the 240sx.org faq and its those that blink, green = 10's and red = 1's. The wierd thing is, it ran a code 55, no manfunction. Soo im not sure what to think now, the check engine light doesnt come on anymore, but im guessing it will in the future. If im not making much sence its because its about 1am, and im tired as heck......

[NISTECH]

if you go past mode 3 it will erase the code. so if by accedent you went through all 5 modes and then started over it had cleared the codes that were stored.

[Toahk]

Yeah I think I did that, at first I thought I was doing it wrong, the check engine light flashed 3 times, then 3 times again, all at the same speed. Would this signify 33? It did the 3 flashes...pause 3 flashes... 240sx.org FAQ says ....33- Exhaust gas O2 sensor circuit Would this mean replace the O2 sensor?

[Holisticbeatz]

If you have an Autozone in your area you can go there and they can use an OBDII scan tool if you have a 95+ model car, they do this free of charge.

How does that tool work?

[NISTECH]

they plug it into the connector under the drivers dash and it pulls codes from the ecm.

[NISTECH]

Yeah I think I did that, at first I thought I was doing it wrong, the check engine light flashed 3 times, then 3 times again, all at the same speed. Would this signify 33? It did the 3 flashes...pause 3 flashes... 240sx.org FAQ says ....33- Exhaust gas O2 sensor circuit Would this mean replace the O2 sensor?

the dashs check engine light will only flash one of the 2 digits. when pulling codes from the ecm manually like that. you need to be looking at the lights in the ecm. one color indicates the tens digit and the other represents the ones digit. you code is a 30 something or a something 3. being you have no real drivability issues it could very well be an o2. since your light is now off from clearing it try driving it till it illuminates again. then follow the procedure listed on 240sx.org

[Holisticbeatz]

they plug it into the connector under the drivers dash and it pulls codes from the ecm.

With that tool, are they able to reset the ECM as well?

[Toahk]

K check engine light is back on, I will pull the code tonight when it gets cool. Its been 100 + degree temp's up here in northern california lately....too dang hot to work outside in the daytime.

[NISTECH]

yea i know what you mean i am near sac and its hot as hell here too. did yard work this after noon was drenched by the time i was done

[NISTECH]

With that tool, are they able to reset the ECM as well?

yep they can erase the codes