hi all,

i posted a while back that i'm building a eureka with a 2l twin turbo subi motor and a manual beetle box. the engine came from a gen 3 auto gtb. car is running and drives.

everything seems to work except i keep getting fault code 38 - torque permission. i've gone through a few electrical diagrams to try to solve the issue but no joy. the following is a list of what i have done. if anyone could help it would be greatly appreciated

2l twin turbo gen 3 gt-b engine automatic computer

only five wires run between the ecu and the A/T controller

1) torque down inhibition - output from ecu of 0v and i have grounded the wire
2) intake air volume - output from ecu of 1v and i have ignored this wire
3) torque down 1 - input to ecu of 5v and i have applied 5v
4) torque down 2 - input of ecu of 5v and i have applied 5v
5) vehicle speed sensor - i have got a sensor that feeds to the ecu

i have also told the computer it is neutral so it will let me start.

if this fails, how can i trick the computer into thinkings its a manual?

cheers,
rob

I set my ECU (1994 Auto EJ22) to think it is in neutral only while it was starting (piggybacked off the starter signal). So once it is running it thinks it is in gear.

Cheers mackaymanx. What's the advantage of letting the ECU think it's in neutral for start? Surely the computer doesn't care if a manual car is in neutral for start? Or does it?

Had a chat to one of the boys from AM Autos and he pointed me in the right direction with regards to the Torque Permission. Went on the hunt for the AT/MT Ident pin and it's all sorted now.

The ECU (auto) won't fire the injectors or igniter if it thinks it is in gear, I just had this problem and the motor didn't fire until after I stopped cranking the engine.

No problem ttriebler. More than happy to share my the knowledge. And as a clause, what I'm about to write is what has worked from me and what I have gathered from a few sources.

There is no difference between a manual transmission ecu and an automatic transmission ecu. It is the exact same 'box'. There is, however, a few minor differences in the wiring to/from it. The main one is the AT/MT ident. This is a lone pin from the ecu that requires an open circuit, ground or power (depending on year model, type etc) to determine if the ecu is meant to run manual or automatic logic. If you want to 'change' your logic to manual, you need to look thoroughly through a correct wiring diagram for your model and find the (MT) wires. The (MT) means that those wires are only applicable to manual logic. I'll attach a picture latter but my AT/MT ident wire was 'near' the injector wiring and required grounding. Once I did that the logic worked well and it thought it was manual and no more 38 fault codes. Now for the clean up. Obviously there are a few excess automatic wires that run to the automatic transmission computer. These are no longer required so I completely removed them. Now for another tricky bit - starter and the neutral switch. Manual and auto logic requires different starter logic so you need to revisit the wiring diagram and see which wires you need to ground or power (and from which source). Finally, the neutral switch. From what I've gathered, the best move is to trick your ecu into thinking it's in gear (once again check your diagram if it requires ground or an open circuit). With these three steps complete you should be able to change your ecu logic from auto to manual.

Now for the disclaimer. Make sure you have the right wiring diagrams, know how to read wiring diagrams, doubel check everything and it should work. If anyone has any additions or corrections please feel free to add.

I will add my wiring diagram later to highlight the wires and areas you should look for.

THanks, that is awesome information and will come in very handy for a lot of ppl.

Having issues loading up the pictures but hopefully my description above should point most in the right direction.

Thanks for the info.