How to force OPEN LOOP mode on OE ECU?? - Toyota Yaris Forums

YarisSedan · 05-27-2013, 08:50 PM

If by open loop you mean when the computer is not looking at your o2 sensors and not in control of the fuel trim you could probably simple disconnect your engine coolant temp sensor to manually keep it in open loop. The ECU dosnt go into open loop till i think it measures thermostat open at 180 degrees or so. Not sure what the yaris reads when the ect signal is loss some cars it will just show hot and turn the cooling fan on all the time. If that dosnt work I would just buy a cheap ect sensor and just have it plugged into the connector sitting there while leaving the factory one installed in the car. It will read then the ambiant air temperature keep the cecl off and fool the computer it will keep it in open loop indefinitely until you plug it back into the stock one.

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05-27-2013, 08:50 PM	#2
YarisSedan Drives: 08 Yaris Sedan Join Date: Oct 2008 Location: California - Bay Area Posts: 2,773	If by open loop you mean when the computer is not looking at your o2 sensors and not in control of the fuel trim you could probably simple disconnect your engine coolant temp sensor to manually keep it in open loop. The ECU dosnt go into open loop till i think it measures thermostat open at 180 degrees or so. Not sure what the yaris reads when the ect signal is loss some cars it will just show hot and turn the cooling fan on all the time. If that dosnt work I would just buy a cheap ect sensor and just have it plugged into the connector sitting there while leaving the factory one installed in the car. It will read then the ambiant air temperature keep the cecl off and fool the computer it will keep it in open loop indefinitely until you plug it back into the stock one.