2005 Prius with DTC P0113

DTC P0113 "Intake Air Temperature Circuit High Input".

This means that either the air temperature sensor within the MAF sensor is bad, or the wiring harness has a loose connection, or the ECM (engine ECU) is bad. I suggest that you remove the wiring harness connector to the MAF sensor (located on the air cleaner housing) and inspect the terminals for corrosion. If you don't see any, reinstall the wiring harness connector and see if the car works OK (you will have to disconnect the 12V auxiliary battery to clear the DTC.)

If the code remains, use an ohmmeter to measure the resistance of the temperature sensor (pins 4 and 5, which are on one side of the connector.) The resistance should be in the hundreds or low thousands of ohms (depending upon ambient temp). The DTC was caused because the ECM believes that the resistance exceeds 156K ohms. If you find that the resistance is too high, then you can feel comfortable replacing the MAF sensor. If the resistance is OK, then look for a bad wiring harness connection which would imply finding the ECM connector pins that correspond to the MAF sensor connector and measuring resistance across the wiring harness run.

If you get to that point I recommend you download the repair manual and electrical wiring diagram info from techinfo.toyota.com which is a subscription website. Good luck.

 

According to the manual, P0113 is Intake Air Temp Circuit High Input. That means the resistance of the IAT circuit is more than 156 kohms

The IAT is the bulb on the MAF





Try unplugging the IAT connector and plugging it back in again. If that doesn't work, remove the MAF from the TB and try cleaning the MAF hot wires and IAT bulb with the approved MAF cleaner

If that doesn't work, the IAT sensor may be Tango Uniform, which requires replacement of the MAF sensor as a unit. Or, it could be a wiring problem too

 

The MAF is here



This is another photo



If the MAF has never been off before, it can stick on the o-ring. It's important to *gently* wiggle it in a clockwise and counterclockwise fashion while pulling out of the TB bore. Don't use a tool, and don't just yank on it

 

I really am convinced that Patrick Wong follows me around PriusChat just to post a technical tidbit before I can. That's ok, keeps me on my toes

 

Seriously, this is how the IAT relates to the ECM



If the resistance of the IAT on the MAF exceeds the value, the entire MAF is Tango Uniform and must be replaced. However, if the resistance at the connector exceeds the value, there is a wiring problem somewhere

Sometimes, connector issues can cause this. Just unplugging the connector and plugging it back in again can help.