we disconnected the crank sensor and scoped the cam signal assuming that we would get a waveform at cranking speed. To our surprise, the engine started and idled perfectly, and also corrected the cam signal voltage in the same way, as the crank signal.
When both sensors are connected, the voltages return to -3 to + 1 etc and engine will not idle.
Is it important for the voltage to read between 0 and 5 v or is the ECU more interested in the cam /crank relationship?
The answer is both, Voltages first to flick the switch / transistor / mosfet gate off and on that converts it to binary and only then can it calculate relationship.
I would like the opportunity to get up close and personal with that vehicle displaying that fault and symptoms. Is that possible ?