Wiring schema for converting 4EAT to full-time Power Mode

[svxistentialist]

Originally Posted by b3lha

Dammit Joe! Don't you ever read any of my posts? LOL I actually traced the wiring for the JDM TCU in my 94.

The power switch on the JDM car grounds pin 4. The SAME PIN as the economy switch on the UK/Aussie car. If you swap your UK TCU for a JDM one then your econ switch will become a power switch.

If you want a JDM diagram, take the UK diagram and modify it as follows:

(i) The switch connected to a4 is labelled "power" rather than "econ", there is no wire to feed the econ light on the dash.
(ii) The speed sensor 2, being a hall-effect type comes straight into pin a11 rather than going into pin a17, out of c6 THEN into a11. The circuit a17-c6 appears to convert the inductive signal to a hall-effect signal on UK cars. The JDM TCU seems to have this circuit but it is not connected.

Phil.

Phil,

Apologies, I DO read your posts, but having connected up the JDM control unit, and finding the speed signal giving me a very "fast" signal on the mileage, i.e. the mileage was clocking up at non-representative rate, I disconnected it, and put back in the Euro one.

Now I appreciate the fast mileage thing was caused by the SS2 signal being fed in whereas the box was set up for the Hall effect one, so my subsequent search for a forced Power mode solution was based on the expectation that the JDM and Euro TCUs are largely the same, and it would be good to find the switching mode to make the Euro box have Power mode full time.

If what you are saying is correct, and possibly also if the US TCU control box is wired similarly to the JDM one because of the Hall effect VSS2 sender, then it is actually possible that grounding a4 on the US one will activate full Power mode, where I would have been expecting Econ mode. {It might be difficult to detect if the US boxes switched on Econ from pin 4, as I imagine their combination meter is not wired up for the Econ light. If grounding the a4 pin switched on the Power light for them, then you would know which way things were hanging}

As I have already tried your JDM solution, and determined that the Power light comes on when the Econ switch is on, can you now tell me how the JDM TCU will accept the in-gearbox SS2 signal, and not give a crazy speed/mileage output? In other words, if I plug in the JDM TCU, do I also need to sever some of the Hall effect connections that are redundant in order to get a meaningful and usable speed signal?

Is it even possible we would need the US TCU to make this Pin 4 grounding give us Power mode without getting a distorted speed output?

Joe