Special problem pulling engine codes (Experts Only)

[ibsorgn]

Can any of you rocket scientists tell me how to pull engine codes from a 2gen 3000GT (OBD1 Hybrid) running a 1st gen ECU. For second Gens the procedure is to short out pin#1 and turn on the ignition and read the flashing codes from the engine check light. 1st Gens you jump pins #10 and #12 and read the voltage deflections from pin #1.

My only concern is don't like the idea of shorting out #1 on the OBD hybrid as it may cause a problem using this mixted configuration.

Appreciate any replys especially from you TT conversion folks.

[RealMcCoy]

What year is the car? what part # ECU? have there been any wire harness changes?

[ibsorgn]

What year is the car? what part # ECU? have there been any wire harness changes?

1994 3000GT SL NA 6G72 which I installed a supercharger on. Wiring is a standard 94 NA harness. This, btw is a all Fed spec car. ECU is a 92 Fed spec TT ecu model was
either MD159966 or MD190663, can't remember I think it was a 9966. No wiring harness changes made other than eliminating a couple pins to make the unit operation. I did however split the O2 signal to feed the two pins required by the ECU. I might add I wired in zener diodes to surpress any possible signal feedback for each o2 pin.

Motor has been running fine for over 2 years but I recently received an engine check light . I have my ideas on what to do but I don't want to say as I don't want to influence anyones replies.

[RealMcCoy]

Pins 112 and 113 (yellow and pink wires) are identical on the 94 NA and the 92 TT ECU connectors. The yellow wire is pin 1 on both style diagnostic connectors.

I don't understand where you got the code gathering info you posted for the first gen? was that a typo? the manual says use an analog volt meter, (I use my 1K Ohm resisted LED lamp) between pin 1 and pin 12. (Actually any ground will work, it doesn't have to be pin 12) So to check codes on your car you would do the same. You would hook the voltmeter between pin 1 and ground, and count the pulses...

[ibsorgn]

Pins 112 and 113 (yellow and pink wires) are identical on the 94 NA and the 92 TT ECU connectors. The yellow wire is pin 1 on both style diagnostic connectors.

I don't understand where you got the code gathering info you posted for the first gen? was that a typo? the manual says use an analog volt meter, (I use my 1K Ohm resisted LED lamp) between pin 1 and pin 12. (Actually any ground will work, it doesn't have to be pin 12) So to check codes on your car you would do the same. You would hook the voltmeter between pin 1 and ground, and count the pulses...

My car is equipt with the OBD2 style (16 pin) port however it is normaly referred to as the OBD1 Hybrid. The procedure for OBD1 came from Stealth316.com, We are on the same page for pulling codes on Gen 1s maybe just stated a little different. So are you saying just follow the Gen 2 procedure?

[stealthee]

You put pins 10 and 12 in your initial post. The correct pins on 91-93 is 1 and 12, but as McCoy said, 12 is just a ground and the pins on the ECU are the same, so yes, use the hybrid "paper clip" method and you will get your codes.

[ibsorgn]

Pins 112 and 113 (yellow and pink wires) are identical on the 94 NA and the 92 TT ECU connectors. The yellow wire is pin 1 on both style diagnostic connectors.

I don't understand where you got the code gathering info you posted for the first gen? was that a typo? the manual says use an analog volt meter, (I use my 1K Ohm resisted LED lamp) between pin 1 and pin 12. (Actually any ground will work, it doesn't have to be pin 12) So to check codes on your car you would do the same. You would hook the voltmeter between pin 1 and ground, and count the pulses...

You know what? I don't know where I came up with the pin#10 thing! I think I got confused reading various pubs and comments. I checked back with the J. Lucius site and you're correct. It was not a typo, more of a brain fart.

[ibsorgn]

You put pins 10 and 12 in your initial post. The correct pins on 91-93 is 1 and 12, but as McCoy said, 12 is just a ground and the pins on the ECU are the same, so yes, use the hybrid "paper clip" method and you will get your codes.

Sorry I don't know what the Hybrid paper clip method is? My concern is one of grounding out pin #1 as that is the pin that is used for sending signals for 1st gens. If in fact the signal is being sent to pin #1 and I ground it, I may wind up shorting something out. If pulling codes for my 1st gen ECU and 2nd gen harness configurations follows the normal 2nd gen procedure then I'm good. (ie, gound pin #1 and watch the engine "check engine" light.

As a after thought, In my configuration, do you think it might be possible to get a signal from pin #1 by using a volt meters probe's on pin#1 for (+) and the other probe to any ground (-) or is it strickly a flashing EC light situation?

Last question, do you have ECU, Harness configuration like mine?

[RealMcCoy]

My car is equipt with the OBD2 style (16 pin) port however it is normaly referred to as the OBD1 Hybrid. The procedure for OBD1 came from Stealth316.com, We are on the same page for pulling codes on Gen 1s maybe just stated a little different. So are you saying just follow the Gen 2 procedure?

No, I'm saying you use the 1st gen procedure with the voltmeter... The ECU You have doesn't flash the CEL for codes. The only change you will make in the procedure, is you will be hooking the positive lead of the meter to pin 1 of the OBDII style connector rather than pin 1 of the OBD1 connector.

[ibsorgn]

No, I'm saying you use the 1st gen procedure with the voltmeter... The ECU You have doesn't flash the CEL for codes. The only change you will make in the procedure, is you will be hooking the positive lead of the meter to pin 1 of the OBDII style connector rather than pin 1 of the OBD1 connector.

OKay, I'll give it a try after this rain storm finishes. BTW, I assume the negative lead to any ground as pin#12 on my ODBII port may not be a ground.