Code 31??

Yeah, i was in the process of doing routine maintenance, and other goodies, and figured, eh lets try the Z31 ECU & MAF (again). Well, to start, i tested the old one. code 55 in mode III. Sweet... Got the Simult. blinking in mode II. ok, air/fuel is good. So, by rights, the z31 one should work, so i disconnect the battery, and put in the set. Starts up fine, idle is a bit high, 1200, but not bad..so i run the diagnostic mode on it..and get 3 red flashes, 1 green. Crap..on the case of the ecu it says Load Signal (as the fault). ..ok?? whats that? Im hoping its not the same as a 31 on the s12 ECU, 31 on the s12 is bad ECU!

...load signal is when you turn on the fan and raise RPM's....try setting it before you start the car,,,it should erase that code.

sorry, im not sure i follow ya...i understand the not getting the signal, but set what to erase the code??

...drop the ECU and turn ignition to "on"[dont start engine].....if code 3-1 comes up, put on the fan and then turn off fan,this should test and clear code 3-1....good luck.

I thought code 31 on s12 ecu was for the fan/air con switch or is it bad ecu??

..bad ecu jimjam..

ok, if its the fan, why would that effect driveability sooo much?

This is the breakdown on Code 31 I got from Z31.com:

31
1.Engine Contrl Unit
2.Air Conditioning Switch
3.Lighting Switch
4.Fan Switch
5.Power Steering Switch
6.Load Signal
1.Abnormal input signals
2.Open or shorted signal circuit
3.Open or shorted signal circuit
4.Open or shorted signal circuit
5.Open or shorted signal circuit
6.Open or shorted signal circuit

So, it could be one of several things. It doesn't go into any more detail than that, unfortunately.

checked the codes, code 31 is for the air con on the s12 ecu (mitchell repair) is this correct or is my book wrong and Ive got a F@#ked ECU

Well, code 31 on an S12 ECU and code 31 on a Z31 ECU may be different. Especially if he's using the ECU out of an 84-86 Z31.

i wanna say something having to do with A/c. i took out ALL of the stuff that was under the hood!

If the car is still running fine, then you're probably right. I've done the same thing as you, removed everything related to A/C under the hood. I'm running an 88 Z31 ECU right now, but I haven't done a diagnostic on it yet.