I have a 2006 F4i with 24200 miles. Recently started having surging issues so checked the FI codes. Got a code for the IAT sensor and the MAP sensor. I went through the troubleshooting steps in the service manual and here's what I found.
For the IAT sensor, measuring the voltage between the two terminals of the connector gave almost 0 Volts. That's supposed to mean there's a short circuit in the wire, but there is continuity between the two ends of the wire. Next issue should be that there is a loose contact on the ECM connector, however it seems fine. I don't really know how to check this except visually.
For the MAP sensor I don't have a test harness, but everything seems fine for the connector itself.
Do you guys think my ECM is shot? Will I have to replace it? Is there any better way to check before I go spend $450 on one of these? Any input/advice would be great.

 

@acorn1 Are you using the Honda service manual? The first check of the IAT has you check the resistance measurement across the pins of the sensor. If the air temperature where you are located is between 68 - 86 degrees ferenheit, then the resistance across those 2 pins should be between 1000 and 4000 ohms. What did yours read?

 

Yes I used it and went through all the checks. I cant remember exactly what I got, but the resistance was around 1400 Ohms.

 

What voltage did you get when checking on the wiring harness side from the Gray/Blue wire to frame ground? Is that the one you are indicating you're getting 0 volts, or only when you measure from the Gray/Blue wire to the Green/Orange wire?

 

I'm got 0 volts for both of them.

 

Did you unplug the connector to the ECU and test continuity from those pins to the IAT 2 pin connector? Should be essentially 0 ohms for each of the wires.

 

What codes are you getting?

 

I did unplug the connector from the ECU and tested for continuity and there was continuity so I'm pretty sure there's nothing wrong with the wire, it's just not getting voltage for some reason. The 2 error codes that I was getting were 1 flash (MAP sensor) and 9 flashes (IAT sensor).