Relay #4 is for LPG intercept valve will have 4 wires, 2 Brown, 1 Green and 1 Black with Yellow stripe.
Here is sequence of operation.
When the ignition switch is in the start or run position.
The 2 Brown wires will be battery + volts from relay 1 and 2.
The black yellow wire will be Battery + volts from pin 112 on the ECM
The green wire (to LPG intercept valve) will go positive battery + volts.
With the ignition switch is in the start or run position, if ECM does not receive continuous signal from crank shaft position sensor for 6-10 seconds the voltage at black yellow wire will go to 0 volts.
The other wire on the LPG intercept valve will be chassis ground.
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