Hi All,

What was the final verdict on this error code - 1621 this is the only code that comes up when I scan my XJR6, is this something I should be concerned about?

Cheers,
Nick

 

"ECM Engine Immobilisation Input Circuit Malfunction"

"A range check on the diagnostic L-line is performed to check for voltages outside expected limits. On detecting out of range voltages the appropriate fault code is stored and the MIL lamp illuminated."

That's all I see about P1621. I don't quite understand what it means, or if it is a real problem.

Is your MIL illuminated? Do you have other symptoms that could be causing the code, like with security or immobilisation?

 

I think P1621 is a sporadic random code.
I spent several weeks chasing this "ECM Engine Immobilisation" error trying to track down a supposed security or immobiliser fault while trying to get to the bottom of intermittent starting (would always crank but not start). In the end this turned out to be a faulty crankshaft position sensor.
The car still periodically logs a P1621 even though there are no issues with it.