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mfiio [2009/03/06 07:10]
twdorris created
mfiio [2024/03/15 11:16]
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-====== MFI Schematic - I/O ====== 
-You can tell from the MFI schematic in the shop manual which pins are inputs and which pins are outputs from the ECU.  This page explains how.  ​ 
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-First, reference the [[http://​www.dsmlink.com/​images/​forums/​2GECUMFI.pdf|2G MFI schematic]] (or the [[http://​www.dsmlink.com/​images/​forums/​1GECUMFI.pdf|1G MFI schematic]]) for an example of what this schematic looks like in the Mitsubishi shop manual. ​ The following is a clip from the 2G manual showing three connections between the ECU and the Automatic Transmission computer (TCU). 
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-{{http://​www.ecmtuning.com/​images/​forums/​atinput.gif}} 
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-Look at pins 43 and 46 on the ECU side.  You'll see a +5v pull up resistor on each input. ​ That means, when nothing is connected to that input (or when the TCU output is "​inactive"​),​ the ECU's sense circuit will "​see"​ 5v.  Which means in order for the AT to "​active"​ that input, it will need to switch the input to ground (which is what the transistor with a connection to ground illustrates on the TCU side). 
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-This all clearly indicates that these pins are "​inputs"​ to the ECU that the TCU is driving as "​outputs"​. ​ So some function inside the TCU will request some function to be activated inside the ECU by pulling those inputs to ground. 
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-And if you'll notice, the two circuits are reversed on ECU pin 7 (AT pin 17), which tells us that that particular connection is an output from the ECU that controls some function inside the AT computer. 
  
mfiio.txt ยท Last modified: 2024/03/15 11:16 (external edit)