Invalid Limit Angle in M1

Invalid limit angle will appear when the start of injection is calculated to cross over the fuel timing limit.

So when you have Fuel Timing Primary Edge (or Fuel Timing Secondary Edge) set to End of Injection, the M1 calculates the the pulse width with the goal of the injection ending at your fuel timing. The limit is how long the pulse is allowed to be extended due to a change in calculation after the injector was already opened (because once the injection has started, you can't calculate the injector to open earlier) - so this can be fuel trims, transient etc that cause a change in pulse width calculation.

 

So if we use 7000rpm as an example:

You are aiming for 650° BTDC to end your injection from the injector. Your timing limit is 130°.

(720°-650°)+130° = 200° of injection window before you will start getting invalid window - which is about a 4.7ms pulse width.

Where, if the end of injection is set closer to the target end of injection, larger pulse widths are allowed before this diagnostic occurs:

Ultimately, the diagnostic should not impact any behaviour, but to rectify it showing up, changing the fuel timing limit to something like this should stop the diagnostic.