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Inconsistent IAT


d1zguy

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My IAT started being inconsistent tonight, going to 100C and coming back in and out. Sometimes it comes back randomly, if I stop it comes back, sometimes its at 100c when first started too. Any tips? Could a loose jumper on J7 cause this? or issues with the board itself?

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Do you mean "Above Error High"?  

This would most likely be a lose connection.  The pin is pulled up - so if you disconnect the sensor the voltage will go high - above the error high value.  

If the J7 jumper was loose it would go low so you would get "Below error low value".  Suggest you connect your laptop and watch the temp value while wiggling/shaking/yanking the loom and all connections you have made.  

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17 hours ago, Adamw said:

Do you mean "Above Error High"?  

This would most likely be a lose connection.  The pin is pulled up - so if you disconnect the sensor the voltage will go high - above the error high value.  

If the J7 jumper was loose it would go low so you would get "Below error low value".  Suggest you connect your laptop and watch the temp value while wiggling/shaking/yanking the loom and all connections you have made.  

So I looked into it, wiring looks okay but rewired my ground. Still the same issue but I figured out the issue.

Issue only happened at night when cold and at or near 16C ambient, once I started driving it would throw the code and show 100C for IAT. I looked at the voltage being put out  by Volt 4 IAT, and it was 4 then 4.01 not 5V as it would if it had lost a ground or wiring issue.

The error high for IAT was set to 4v IAT errored out when it went below 17C which is 4v 4.01v. So I simply set the error high voltage to 4.5v and it solved the issue. 

Was driving me nuts as to why if I stopped for a bit and let it idle it would start reading then as I drove it would error out again. Made perfect sense letting it idle decreased the voltage and increased IAT temps; as I drove and that cool air made it past the IAT it would get to 4v and make the link think it errored out instead of displaying 16C or below. If anything it shows how responsive and fast the link IAT is lol

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