GVR-4 Coolant temperature erratic on MMCD with one ECU

[4gfun]

I purchased a CA/MT/Turbo/1g ECU from someone a while back that was rebuilt. Good guy.

Recently I notice that the coolant temperature is fluctuating. It gives me 72 degrees and then 176 degrees. Random things like that.

It would seem to be an obvious problem with the Coolant Temperature Sensor, however my other ECU reads it just fine.

Any idea what might be internally wrong with that ECU?

The socket is fine.

Thanks!