Only starts in diagnostics mode ????

[GTS69]

hey guys just put a lower km motor in my car i used the computer and bcm i already had just swaped out motor and auto i now have a problem where the car will only start in diagnostics mode and when in diagnostics but i dont start it there is no fault codes showing the engine light just stays on but if i start it there is not engine light on any ideas ???

[mr031]

What about the key head?

[GTS69]

key head is still the same programed to the bcm and computer thats in there

[Jxw]

check all the plugs, ground points, if in doubt dc them make sure they're clean, not corroded or bent pins causing a bad connection.... dfi module, crank sensor, oil switch & main gnd from batt to engine block? you only swapped the motor so it's possibly a bad connection somewhere.... maybe a bad sensor in the donor engine

[GTS69]

done all the checks on every connection and wire engine ran fine in donor car and i drove it to work in diagnostics mode and back no issue everything worked fine i had a tech 2 tool pluged in and it came up with security and stuck in 3rd but again all works 100% in diagnostics go figure