All

 

Please forgive me if this is a duplicate or stated somewhere already.  I drove home about 3 hours last night and as I pulled into the driveway my check engine light came on.  I had my High Idle Kit in MPG mode during the entire drive and did not notice anything out of the norm.  This evening I pulled the codes and found P0113 and P1693.  After work (cold engine as I didnt drive it today) I noticed with the High Idle Kit in the "OFF" position my Intake Air temp was showing -40* on my ScanGuageII (temp outside around 60*F).  The truck also went into 3 cylinder mode shortly after.  Would this be a bad IA sensor or something more complex?  Any help is greatly appreciated.

 

Thanks,

 

Tim

Double check you connection. Then clear the codes. It possible to set codes turning the selector knob too slow between settings. If still having problems submit support ticket we'll deal with the issue.

Hey Tim

Access the board

Pin out Molex connector looking at it straight on

 

8   7    6    5

X   X   X   X  

X   X   X   X    this is the bottom of the board as you look at this connector

4   3    2   1

 

The switch OFF posistion check continuity at the following pins

 

Pin 1 and 5 = 0 ohms

Pin 2 and 3 = 0 0hms

 

The switch in posistion 1 (MPG)

 

Pin 1 and 4 = 2.2K

Pin 2 and 3 = 0 ohms

 

The switch in posistion 2 (6 cyl High Idle)

 

Pin 1 and 4 = 39K

Pin 2 and 4 = 3.3K

 

The switch in posistion 3 (High Idle 3 cyl drop out)

 

Pin 1 and 4 = 55K

Pin 2 and 3 = 0 ohms

 

If you do not see these values in any test posistion as noted above get some contact cleaner ****** your switch and hit it gently with compressed air to dry...then re-test as above and confirm the resistance values.

Plug your control cable back into your board and remount into posistion.

Grab your Smarty and clear your codes.

Restart your CTD in posistion 2 and observe the ramp-up idle function.

You should not see any codes appear and all will be normal.

If NOT then you have harness continuity testing and or ECT or IAT out of spec's to review.

I use Keg contact cleaner available from some Radio Shacks or Mouser and DigiKey carry it...it is the best product.

 

Cheers,

William

 

 

 

 

 

@Mopar1973Man I reseated the connections yesterday at lunch with the same issue.  I did not think to fully disconnect the High Idle Kit to verify if the issue still existed without the kit.  I can do this tomorrow if you would like, as I will be out of town tonight with work.  

 

@W-T Thanks for the write up, I did not have time to test this during my lunch break but will verify this tomorrow evening as well.

So I have disconnected the High Idle kit completely and have noticed the Intake Air temp is still showing -40* and fluctuating up to about 115*  Would this be from the grid heaters cycling?  Also with the -40* IA temp would this mean the sensor has gone bad and need replaced?  It is no where near that cold.  Also the connections seem to be snug, so I do not think this is a loose cable issue.  

 

I do not think the High Idle kit has any issues, as when i flip though the settings the ScanguageII shows the respectable water/IA temps that it is supposed to be fooling.  I was going to test with a volt meter at @W-T suggested, but I needed a third hand to hold the switch and another person was not available at the time.  

Check for a break in your IAT wiring to the ECM and ground.   I would prob the IAT wire checking for any shorts etc.  

The ITA sensor is a negative temperature coefficient sensor.  There is a resistor in the sensor called a thermistor.       The ECM supplies 5.0 volts to the sensor and as the temperature increases the resistance in the thermistor decreases allowing electricity to flow more freely and a higher voltage return to the ECM. 

The colder the temperature, the higher the resistance, the less voltage return.

This change in voltage is used by the ECM to for idle, and injection management.  

A -40° temperature reading when you know the outside air temperature is warmer indicates a very

high resistance, open circuit, and no voltage return to the ECM.  

 

5 hours ago, Me78569 said:

Check for a break in your IAT wiring to the ECM and ground.   I would prob the IAT wire checking for any shorts etc.  

Check as above first If no problem found in the connectors/wiring then it may be an intermittent open circuit in the sensor and the sensor needs replacing.  All the NTC sensors I've seen go bad have tested opened circuit and read -40°.

Thanks everyone for all the advice so far.  I did not notice any shorts in the electrical, so I am going to replace the IAT sensor after work this evening and see if that works.  Ill update everyone after this gets completed. 

So replacing the IAT sensor fixed my check engine light.  Thanks everyone for the help.