ECM, where is it?

[DrIfT_FoReVeR]

i know this is kinda n00bish...but i read in the FAQ section about checking for error codes via the ECM, and resetting it as well.(http://www.240sx.org/faq/articles/ecm_reset.htm)i put a cold air intake on, and my friend said i needed to reset the ECM so i dont completely screw over my gas milage or anything else...i also need to check for any trouble codes because i have this knock in my engine under my valve cover...anyway, can anyone point me in the right direction?

i need a little more detail than "the piece of plastic by the passenger foot"...what is a passenger foot anyway?

BTW I looked on the passenger side where the passenger puts their feet (lol its starting to sound like engrish...) and i only saw pieces of plastic that were attached firmly, and since it was 4:30 in the morning, i didnt feel like screwing with all that.

can anyone please help me? thanks...also, if i sound *****y, im sorry, its late and i need to get to bed.

thanks again.

[NISTECH]

this picture was for another post but in it is the ecm as well.

[DrIfT_FoReVeR]

ok, that picture helps a lot, but im still stuck. i took out the glove box and the little metal frame that was behind it, and i see a huge black box, and nothing that resembles the ECM in the picture. can you or anyone else kinda give me a push in the right direction? i need to know, basically, what i need to take out to get to it, and what i need to look for.

thanks!

[mattdesmond]

It's under the passenger side kick panel on the right side. you'll have to undo the 2 screws that hold it to the side and flip it around and that's where the LED's and control knob are.

[DrIfT_FoReVeR]

ok cool, i found it, and everything checks out fine...one question though, when it blinks, it goes: blink blink blink blink blink...blinkblinkblinkblinkblink

does that mean a code 55 or is that just the 5 different diagnostic settings?

btw the check engine light and the red LED was blinking...i looked a little harder, and there is no green LED where one should be...almost like it was taken off the motherboard of the ECM...this is a problem, i assume...am i right?

[mattdesmond]

Self-diagnostic system can be operated in one of 5 modes.Modes are manually changed using screwdriver through access port onECU. With screwdriver turned fully clockwise, inspection lights willbegin to flash. Count the number of flashes. First flash is mode I,second flash is mode II, etc. When desired mode has been indicated,turn screwdriver fully counterclockwise. In different modes, Red andGreen LED’s perform different functions.

MODE I (MALFUNCTION WARNING)This is the normal vehicle operating mode. Green LED willindicate loop status. If LED is not blinking, vehicle is in open loopor there is a fault with the oxygen sensor or sensor circuit. If LEDis blinking, vehicle is in closed loop. If a malfunction occurs inMode I, Red LED and check engine light (if equipped) will illuminate,indicating an ECCS malfunction has occurred.MODE II (EXHAUST GAS MONITOR)In Mode II, both Red and Green LED’s are used to monitorair/fuel mixture feedback control. Green LED will function the same asin Mode I. In open loop, Red LED will remain on or off along withGreen LED so vehicle must be in closed loop in order for Mode IIresults to be valid. In closed loop, Red LED will indicate if systemis running rich (light off), lean (light on) or if at the idealair/fuel ratio (blinking synchronized with Green LED).MODE III (SELF-DIAGNOSTICS)When Mode III is accessed, codes stored in ECU memory will beflashed by the Green and Red LED’s on the side of the ECU. Red lightwill flash the 10’s column digit, while Green LED will flash the 1’scolumn digit. For example: 3 flashes of the Red LED, followed by 5flashes of the Green LED would indicate a Code 35.MODE IV (SWITCH CHECK)This mode is used for checking ECCS switch status. When theidle switch, starter switch or vehicle speed sensor are activated, theRed LED will come on and go off as the status changes.MODE V (TEST MODE)Mode V represents a real-time diagnostic test of the crankangle sensor, ignition signal, airflow output signal and fuel pump.This mode is accessed for an in-bay running test of the vehicle. TheRed & Green LEDs must be monitored carefully during this test, withspecial attention paid to the number of flashes before each pause.The malfunction code will be displayed only once and willnot be stored in memory. If Red LED blinks on and off evenly, thisindicates a fault in the crank angle sensor. If the Red LED flashestwice before a pause, this indicates a fault in the airflow meter. Ifthe Red LED blinks 3 times before a pause, this indicates a fault inthe fuel pump circuit. If the Red LED blinks 4 times before a pause,this indicates a fault in the ignition signal.ENTERING SELF-DIAGNOSTICSNOTE: When engine is running, it is not possible to switch modes.When ignition switch is turned to OFF position, ECU willswitch back to Mode 1.DUAL LED SYSTEM (5 MODES)1) Turn ignition switch to ON position. Use a screwdriver toturn ECU diagnostic mode selector fully clockwise.2) Wait for inspection lights to begin flashing. At thistime, inspection lights will flash the mode options (i.e. 2 flashesfor Mode II, etc.). As soon as inspection light flashes the desiredmode number (3 flashes for Mode III), immediately turn mode selectoroff.3) If the mode selector is kept in the ON position, the modeselections will continuously cycle (Mode I to Mode II up to Mode V,then cycles to Mode I, etc.) and the process will continue. This willnot erase the memory.RETRIEVING CODESDUAL LED SYSTEM (5 MODES)Trouble codes are read using the Red and Green LED inspectionlights on the side of the ECU. After selecting Mode III, trouble codescorresponding to that mode will start flashing. Trouble codes areindicated by the number of flashes from the ECU Red and Green LEDinspection lights. Count the number of flashes. The Red LED indicatesthe number of tens while the Green LED indicates the number of ones.For example, 3 flashes of the Red LED followed by 2 flashes of theGreen LED would indicate code 32.

[Avatar30]

Hey there Drift, fellow Houstonian here, just displaced in Seattle right now. The post above refers to the SOHC ECU. Follow this link here to the DOHC ECU and how to read it http://www.240sx.org/faq/artic...h.htmI myself just learned this today as well. If you don't have the green led, then you should have the DOHC model as the SOHC ECU does have both led's. Also, you're correct, your first set of slow flashes is your first number, the second set of quicker flashes is the second number (note the check engine light will flash in tandem with the ECU, it's suppose to, don't worry) Oh, btw, a code "55" means as far as the ECU knows, everything is ok. On the page that I provided the link for is a list of codes as well. Just in case though, here's the link for the SOHC http://www.240sx.org/faq/articles/ecmcodes.htmGood luck

[DrIfT_FoReVeR]

oh, cool! my car is fine according to the ECM...or is it an ECU? is there a diff? ive heard ECM and ECU in this topic referring to the same thing. anyway, everything's fine! kick ***!

[NISTECH]

Manufacturer terminology. some call it ECU some call it ECM they both mean the same. Nissan calls it an ECM. You may catch me calling it both,I have been trained on other lines of cars as well so I mix all their terminology up all the time. like MAF and MAS they both mean the same thing.

[Altiman94]

ive also seen mafs for maf and mas being the same thing