If the ECU sees RPM signal (G28) above a certain speed it enables the fuel pump - I logged this in another thread on subject of 'engine simulator' if you wish to learn more details. This is to stop fuel pump in a heavy shunt that stops the engine while ignition is ON. You can only really test G28 with an oscilloscope. Again I have captured that waveform before here - no mystery that its a sawtooth shape derived from 135 teeth per crank revolution.
The ECU uses the hall signal (CMP/G40) as the gate to define what phase the engine is on for timing of cylinder #1 - the crank position cannot do this alone for obvious reasons. Best way to test G40 is with 5V LED between pin 2 and 0V - it should blink off every other crank rotation. If the ECU doesn't know where the camshaft is, it cannot determine a firing position.
So in short form -->
if G28 is dead you get no fuel pumped
if G40 is dead you get no sparks
The ECU uses the hall signal (CMP/G40) as the gate to define what phase the engine is on for timing of cylinder #1 - the crank position cannot do this alone for obvious reasons. Best way to test G40 is with 5V LED between pin 2 and 0V - it should blink off every other crank rotation. If the ECU doesn't know where the camshaft is, it cannot determine a firing position.
So in short form -->
if G28 is dead you get no fuel pumped
if G40 is dead you get no sparks




on pin 2 (+V) and pin 3 (0V) and when ignition was turned on it lit up and stayed lit up even with the engine turning over. So it looks like a new G40 is in order.
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