Climacab fan comes on an shoots code 1402 then shuts down with is code 0400 .

Nothing online. Phone their Customer Service

http://truckspecialtycenter.com/wp-content/uploads/ClimaCabInternational.pdf

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Was there a letter in front of that code? Possibly a letter 'P'? If yes, the code refers to the electronics for your Exhaust Gas Recirculation (EGR) system.
P1401 = EGR Valve Circuit Short to Ground.

Should be under the hood. This seems to be pretty common so your local dealer should know exactly what going on if you tell them the story.

0105 - MAP/BP Circuit Malfunction
0400 - EGR Flow Malfunction
0500 - Vehicle Speed Sensor Malfunction
1405 - DPFE Sensor Upstream Hose Off Or Plugged

P0300 Random Misfire, means any cylinder at anytime.

P0400 Exhaust Gas Recirculation Flow. EGR passages are full of carbon
clean passages and misfires may go away

P0443 Evaporative Emission Purge Control Valve circuit.

now just because a code is present doesn't mean a part/sensor is bad, just where to look and to test.

P1401 EGR Control Solenoid Circuit Signal Low

You have an electric cooling fan - this is normal for this to occur. Do not be alarmed. The fan is controlled by a thermostat. If your fan continues to run after 20 minutes then I would trace the wires, and check the connections to the thermostat. Verify the reading across the terminals are out of spec before replacing it. First, time the fan to see how long it runs for - just sit there and look at a magazine while you wait - it shouldn't be that long. When you hear it stop, look at your watch. If it's more than 20 minutes (I sincerely doubt it will run that long) then trouble shoot the thermostat as mentioned previously.

your local auto zone can read your code. you will need this code to trouble shoot, as there are many things that can cause this. your toyota is obd1 so call and ask if they can read your code before driving out there in your vehicles condition. most just have obd2 scanners (1996 and newer)

What you can try first is disconnecting your battery cables(positive an negative).. What that does is reset your comuter..then re attach the cables and start the car to see if light comes back on.

I fixed it by buying a new EGR valve and the codes have not returned.