Quote:
Originally Posted by Villeh
Should I get error codes if I have polestar installed?what is checksum error? Doesn't that turn the engine light?
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Yes, any change to the Flash RAM contents which deviate from the factory delivery will produce a Checksum Error.
The Checksum Error does not produce a Check Engine light (maybe because the tuner they deprioritised the alarm, or maybe it never did cause a check engine light)
To learn what a Checksum is, see wiki:
https://en.wikipedia.org/wiki/Checksum
A checksum is used to verify data integrity, and it is exactly the integrity that gets changed when a tune is applied.
Thus the checksum error is a positive confirmation that the tune exists.
This is true for the 2002-2015 XC90s and the type of ECM fitted to them, as most tuners cannot or do not update the ECM checksum to avoid the checksum error.
Other cars and/or other tuners may be able to update the checksum. It all depends on what ECM is fitted, and where the checksum exists, and if it is updateable.
If the checksum gets updated during a tune, then no checksum error will exist.