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I hear you Anders. I'm definitely not rushing this. I have two complete wiring diagrams printed and marked up, along with the diagnostic diagrams for TB, MAP, and a few other sensors. The wiring harness from the ECU to the engine is completely stripped for access. It looks like Armageddon in the engine compartment.
According to WIS, pins 69 and 46 should be sending 5v to the TB, to pin 2 (red/grey wire) and pin 7 (black/white wire.)
With the key on, If I unplug the TB connector and check the terminals in the connector, I don't have 5v on these wires at the TB, and I have probed them from the ECU to the TB, and they don't have 5v at all.
Contrarily, I get 5v on pins 1, 3, 6 and 8 at the TB. According to the TB diagnostic diagram, pins 6 and 8 should be returning the voltage FROM the potentiometer(s) to the ECU. Therefore I would expect no voltage, or at best only millivolts.
According to WIS, the 5v supplies are coupled inside the TB, so "no symptoms will appear if there is a break in just one of the circuits." This suggests that I have a fault in both of these circuits.
The only component on the ECU 5v supplies that I have not checked (and replaced with new) is the tank differential pressure sensor. I suppose this wire could be shorted (although I can't see how I did that in the process of removing and replacing the engine and transmission), and if so could be causing the loss of 5v on the black/white wire at other components. But why is there 5v on pins 1,3,6 and 8 when the TB connector is unplugged? And this would be only one of the 5v supply circuits, so per WIS should not cause the TB to go into limp home.
I've come home to collect my laptop so I have WIS and I'm headed back to the shop. I'm going to disconnect all the components that get 5v from ECU pin 69 and 46 and see if the 5v returns.
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