PSM ABS warning light on 996 turbo.

[aquaregia]

This seems to be an ongoing issue. The PSM light ABS light coming on. Started with rough hunting idle. So jobs done to correct.
Alternator changed, new alternator strap, new MAF sensor, new battery. Brake pedal switch changed.
Both lights on again. Error code read MAF tried a new genuine bosche MAF still got code. Code error still points to MAF.
Anyone had this issue?
Any help really appreciated. I live in Dubai, hot and dusty conditions.
I have noticed some slight rev fluctuation, but that's it.

Any help would be really appreciated.

[JFP in PA]

Do a voltage drop test across your primary battery/starter cables; well known for causing voltage problems in the heat, and voltage excursions will trip the ABS/PSM lights