Can anyone please explain what might cause the message 'Incorrect Part Fitted' to appear on the message display on the dash?

Thanks

Andy

 

In my case, it was a poor connection on the bottom side of the left engine fuse box. (That caused a voltage division under load allowing partial voltage across the TCM and the remaining voltage across that poor connection). I cleaned all of those connections on the box and and have had no issues since (years). In general, a poor connection may cause a correct part to be reported as incorrect.

 

A weak battery is often the cause also.

 

Thanks Dr.D, you've given me something to think about and check.

I'm happy it's not the battery, I gave it a good charge the day before I last hooked up the laptop and it's resting at about 12.7 volts.

Andy

 

Just a heads up for anyone doing similar test, Front probing with a voltmeter may indicate incorrect (no load, supply voltage )readings. You Tube has many videos on the strength of back probing over front probing to determine true voltage under load. (probably ranging from the supply voltage to much less, depending on the resistance within the connections)