OBD Workaround question - Honda Prelude Forum

freefaller · 08-01-2002, 11:35 AM

This probably sounds a bit stupid, but here it goes- I did the OBDII workaround a few months ago (its on the ntpog page) and put in a switch to turn the memory recognition thingie on and off-- problem is how can you tell if is disabled? I've taken the car in to the dealer a few times since then and have thrown the switch to what I think is the on position and they havent said anything about the ECU not responding. I think I've got the switch thrown the right way but would like to make sure. Is there anyway to test it to see if the memory is disabled?

freefaller · 08-01-2002, 02:23 PM

comon--somebody?

TyWebb · 08-01-2002, 02:40 PM

This is probably not the easiest way but it works.

1. unplug electrical connector from EGR Valve (left side of intake manifold)
2. Put switch in what you think is "on" (closed circuit)
3. Start engine, drive around for 5-10 minutes.
4. Shut off engine.
5. Start engine, drive around for 5-10 minutes.

If you get a check engine light, you're gravy.

Or how about just check the voltage on the ecu side of the switch?

xxH22Axx · 08-01-2002, 03:00 PM

If you'd PM marcucci (todd), he will tell you all you need to know. He is the one who did the write up on it and he could do it with his eyes closed prolly.

ton_e69 · 08-01-2002, 05:06 PM

There is a much easier way to find out... The switch just takes away the 12V constant power that goes to the ECU. Take a test light, ground the alligator clip side and check if its a through circuit. If the light goes on from both posts of the switch..your on...if theres only light when your on one post of the switch, but no the other its off. The same concept using a mutlimeter, but of course its voltage readings or no voltage.

The create a engine code method mentioned works to, but you dont need to drive around to check it. If you start your engine and pull the plug on your throttlebody, next to the intake tube, youll create a error code.( turn off the car, then plug it back in) If the code stays after you turn off your car and restart it, its on...to clear the code flick the swith off then back on.

Hyojiggy · 08-01-2002, 05:30 PM

how long do you have to keep it "off" to reset the ECU?? or is it instantanious?

djc · 08-01-2002, 07:02 PM

freefaller - look at your switch. Is the circut broken or not? In other words... if your switch is on the side where both wires on soldered on, then the circut is on, and the electrical current goes thru. If the switch is on the side where one wire is soldered on, and the other is an empty prong, then its off. (according to the NTPOG switch diag.) if your switch is different, or another easy way to do it is get out a voltimeter and test it.

Hyojiggy - If you pull your 7.5 fuse, then let sit awhile. With the workaround, it doesnt really matter cuz everytime the car turns off, the ecu will forget. When I was pulling the fuse, it wouldn't reset sometimes cuz i put the fuse back in too quickly.

marcucci · 08-02-2002, 06:41 AM

Test lights are bad ****. You should NOT use one in ANY modern computerized car unless you REALLY know what you are doing. It's a good way to fry your ECU.

Most toggle switches have the "lever" pointing AWAY from the shorted contacts. The two wires should be coming out of the end of the switch pointing AWAY from the toggle when the switch is "on" and you are taking it to the dealer.

ton_e69 · 08-03-2002, 03:15 PM

Quote:

Test lights are bad ****. You should NOT use one in ANY modern computerized car unless you REALLY know what you are doing. It's a good way to fry your ECU.

Thats, true..for some it might be best to use a multimeter, test lights and airbags are the main reason you shouldnt use a test light, plus it can cause shorts if not used properly. Good call!

freefaller · 08-04-2002, 02:34 PM

thanks guys-- I used a smaller rocker switch instead of the one used in the write up-- its smaller and hides better under the glove box. thanks again

flybyeludegettingirls · 08-04-2002, 03:36 PM

will the check engine light light up if you have the obd2 workaround??? or is it that it just won't show what code for the problem but the light will still go on???

LUDECHICA · 08-04-2002, 04:06 PM

IS there anymore info on this

axion68 · 08-04-2002, 04:09 PM

Quote:

Originally posted by flybyeludegettingirls
will the check engine light light up if you have the obd2 workaround??? or is it that it just won't show what code for the problem but the light will still go on???

well, there are 2 positions on the obdII workaround. there is the remember mode and the forget mode. the remember mode will remember a cel when you start your car up, but the forget mode will not remember any cels when you start the car up. I believe you will still get a cel if something happens, but it will forget it when you shut the car off.