Thread: BCU, ECU & TCU for 4.6 from USA

I'm completely lost seing those random fault codes which are different from one reading to another and the change has no logic as long as there was no intervention in the previously shown fault area... the open loop thing seems to be caused by that missing O2 sensor input cos at least those codes are permannent:

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The ECM will also go into open loop fuelling if a HO2 S fails.
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Originally Posted by Eevo

why not get the coolant temp sensor working?
will run better if the ecu knows the current coolant temp compared to a fixed value from a resistor.
and will allow it to get closed loop once its above 65 degrees.

This is a sensor that was only on NAS models located in the bottom of the radiator to measure water temp in that area. So there is no sensor or plug on my UK spec car. So I can't get it working Eevo.

Originally Posted by sierrafery

I'm completely lost seing those random fault codes which are different from one reading to another and the change has no logic as long as there was no intervention in the previously shown fault area... the open loop thing seems to be caused by that missing O2 sensor input cos at least those codes are permannent:

I think it just wasn't meant to be.

Now I can't get the original ECU to work. Something going on with the immobiliser and won't learn the code from the BCU (which came with the 4.6 ECU as a matched pair).

Originally Posted by Battler

I think it just wasn't meant to be.

Now I can't get the original ECU to work. Something going on with the immobiliser and won't learn the code from the BCU (which came with the 4.6 ECU as a matched pair).

That's strange, can you communicate with that BCU? ...go into it and disable the immobiliser completely(set to not fitted)

Originally Posted by Battler

This is a sensor that was only on NAS models located in the bottom of the radiator to measure water temp in that area. So there is no sensor or plug on my UK spec car. So I can't get it working Eevo.

buy sensor
drill hole
???
profit!

without that sensor, how will it ever know to run closed loop?

Originally Posted by sierrafery

That's strange, can you communicate with that BCU? ...go into it and disable the immobiliser completely(set to not fitted)

Yep, I just finished doing that and it now starts and runs.

Very good tip though as I just stumbled on that by accident. My theory was if I disabled the immobiliser it would start. Nope. So I enabled the immobiliser and then asked the ECU to the learn code. Starts. Thanks.