My 96 Mazda Protege failed to pass CA Smog test because the PCM Monitors hadn't 'reset'. I've driven it 3K miles, and they just won't reset. I took it to the dealer and he said it was over-heating and needs a new coolant temp sensor. I've replaced both of them. Unfortunately there was never anything wrong with the Temperature Sensors. The fuse for the Fan had been removed. I've since heated up the engine to over 205 degrees, and the fan comes on.

The PCM isn't displaying any malfunction codes. The MIL doesn't light up, and when I hook up an OBDII monitor, there are no codes. The OBDII monitor does show that the Catalyst, Evaporative System, Oxygen Sensor, and EGR System monitors are 'not ready'
The Misfire, Fuel System, and Comprehensive Components monitors are all 'Ready'. The 'Oxygen Sensor Heater' starts out 'not ready', and is the only Non-continuous Monitor that DOES transition to a 'Ready' state.

At this point I'm guessing that the PCM (Powertrain Control Monitor - i.e., computer) is malfunctioning. I've pulled it, and opened it up, and it looks fine (visual inspection - no corrosion or visible damage).

Does anyone know the order in which the monitors are reset? I'm wondering if the next monitor in the series is malfunctioning, and preventing the rest from resetting. Perhaps just replacing the EGR System sensor (for example) would fix the problem and allow the remaining sensors to reset. I'm guessing.