3cyl high idle Electrical bug! Bad ECM

[JP907ATB]

1998 cummins 5.9 24v having problems with po113 code, cannot erase, IAT sensor reads -40 in live data. That reading dose not change if i unplug the sensor, leave it plugged in, or put a jumper in the IAT plug, it reads -40 no matter what. I am pulling 4.8v on my multimeter at the IAT plug with both test leads in connector. I put a 2.7k ohm resistor in IAT plug and i can clear the po113 code and run truck, forcing IAT to read around 114. How ever something is forcing the truck into high idle and then what i believe to be 3 cyl high idle.  It dose this if i run truck without resistor in and check engine light on to. I have checked continuity on both IAT conector wires back through ecm plug, along with the wires for the CTS and MAP sensor. They all tested good when i ohm tested them. I have also replaced the IAT sensor CTS and MAP sensor. I pulled IAT sensor and check resistance on it and it seemed good still as the reading dropped when i put heat to it with blow dryer. I also took alternator to local Oreillys and had it bench tested 6 times and it passed every time, (i knew for sure it was charging but thought maybe bad diode.) Also have to brand new batteries, and have researched ground locations and cleaned every single one to shinny metal.The truck also has smarty but programmed to stock, along with edge juice with aditude which is completely disconnected. However before i disconnected it completely it said the ecm was getting 14.2 volts with truck running is that normal? Also the truck has a high idle kit of some sort installed but it works fine, actuator type mounted under throttle housing. It only allows high idle at 1200 rpm and works fine whe. Engaged and dis engaged. I have run out of ideas any input would be greatly appreciated.

[Me78569]

Follow this troubleshooting.  

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/obdii-error-codes_94/p0113-intake-air-temperature-sensor-voltage-too-high-r38/

[JP907ATB]

Okay i found this guide and followed these steps. However i do not have drb3 tool.(wish i did) I did all the testing back probing.  I believe i read less then one volt at IAT connector with key off, but i put two different new IAT sensors in and pulled them back out and tested with blow dryer, as well as compared to chart in manual. I have the second new IAT back in now and believe it to be good. However i did miss step 5. I have less then 10 ohms on the black and light blue wire, which is IAT ground. I also have less then 10 ohms on my grounds to MAP and CTS. Also, sometimes. When i first turn on my ignition my CTS also reads -40 but then goes to the normal outside temp after a minute,But it doesn't do it all the time. If i plug my edge back in it reads a normal iat and CTS reading even though my scan tool always shows IAT at -40

[Me78569]

you can do it wihtout the dbrIII, just follow the guide with a multimeter. 

[Mopar1973Man]

I'm going to have to say that your ECM is shot. 

 

47 minutes ago, JP907ATB said:

That reading dose not change if i unplug the sensor, leave it plugged in, or put a jumper in the IAT plug, it reads -40 no matter what.

 

That tells me the sensor side that creates the 5V signal is not seeing the ground signal at all. Double check the wiring for opens. In other words unplug the ECM and the IAT plug and ohm from pin to pin and see if the reading is ZERO ohms. If so the wiring is fine but the ECM is damaged.

[JP907ATB]

Thank you for the quick responses! I have triple check the wiring now with my multimeter,i believe the wiring to be good.  My multi meter bounces from 00.0 to 00.4 and sometimes a little higher, when i touch the two probes together. It normally settles around 00.0-00.3. Which is also the reading i got when i checked the signal, and ground to IAT.

This is a short video of the truck running with 2.7k ohm resistor in IAT plug fooling it to read around 114

IMG_0028.mov

[Mopar1973Man]

I'm going to say your ECM is gone. The sense is gone for IAT...

[GSP7]

Who are you going to get a Remanufactured ECM from ?

 

.

Edited December 9, 2017 by GSP7

[Chris O.]

Okay so i'm shooting blind from my memory here but i believe if you disconnect a sensor they should be staying at high state (5 volts) which means closer to +314f on a scan tool at least this is what's happening on PCM not sure about ECM.

This sounds like a short (wiring harness?),  you should follow service manual wiring to figure out how many more sensors are connected on the IAT circuit.

 

[JP907ATB]

Don't know I wasn

5 minutes ago, GSP7 said:

Who are you going to get a Remanufactured ECM from ?

 

.

I wasn't ready to accept that as my problem lol. I have seen a few forms on here talking about the subject but haven't researched yet. I know oreillys will sell me one for 400$ but then dealer has to flash it(in the truck) which means labor time at dealer $$$$. Anyone know if  my smarty would flash the new ecm?

3 minutes ago, Chris O. said:

Okay so i'm shooting blind from my memory here but i believe if you disconnect a sensor they should be staying at high state (5 volts) which means closer to +314f on a scan tool at least this is what's happening on PCM not sure about ECM.

This sounds like a short (wiring harness?),  you should follow service manual wiring to figure out how many more sensors are connected on the IAT circuit.

 

I think it's the CTS and Map are on the same circuit as the iat 

Edited December 9, 2017 by JP907ATB

[Me78569]

 

[Chris O.]

I just did a quick check in 2001 Dodge Ram service manual, it looks like this sensors share the common ground:

INTAKE AIR TEMP SENSOR - ENGINE OIL PRESSURE SENSOR - MANIFOLD AIR PRESSURE SENSOR.

page 8W - 30 -33 and 8W - 30 - 32

S165

 

Edited December 9, 2017 by Chris O.

[Dieselfuture]

14 minutes ago, JP907ATB said:

I know oreillys will sell me one for 400$

Wow I didn't know they sell ECMs and that cheap. I guess I never asked ether. I would highly recommend trouble shooting wireing and whatever else like suggested before committing. I thought my vp was bad 4 years ago was about to change it but good people on this site had me do few things and it ended up being between ac noise and injectors. Wish you luck.

3 minutes ago, Chris O. said:

I just did a quick check in 2001 Dodge Ram service manual, it looks like this sensors share the common ground:

INTAKE AIR TEMP SENSOR - ENGINE OIL PRESSURE SENSOR - MANIFOLD AIR PRESSURE SENSOR.

page 8W - 30 -33 and 8W - 30 - 32

 

Yes that reminds me someone reported a problem with internal leaking of the oil sensor that was screwing with 5v loop so I changed mine just in case lol. 

Edited December 9, 2017 by Dieselfuture

[Me78569]

that was me.  the oil pressure sensor shorted internally and caused the entire 5v system to go wacko.

[GSP7]

O rileys gets crappy Cordone rebuilt ECMs, . and they are not programed to your Vin#

 

And I was told they dont have them for Cummins dodges anyway.. And I would not buy Cardone anyway

Edited December 9, 2017 by GSP7

[JP907ATB]

1 minute ago, Me78569 said:

that was me.  the oil pressure sensor shorted internally and caused the entire 5v system to go wacko.

I haven t checked this sensor or wiring yet. I think the CPS is on this circuit as well i will have a look at both of theses sensors and the wiring 

9 minutes ago, GSP7 said:

O rileys gets crappy Cordone rebuilt ECMs, . and they are not programed to your Vin#

 

And I was told they dont have them for Cummins dodges anyway.. And I would not buy Cardone anyway

So where did you order yours from? We have the same nightmares as far as ordering junk or faulty equipment. And i only want to do it once of i have to.. lol i was trying to pull part number off it and its flaked off so i can't read it. But oreillys said that they can get them for the cummins but need OEM part number 

[GSP7]

10 minutes ago, JP907ATB said:

So where did you order yours from? We have the same nightmares as far as ordering junk or faulty equipment.

 

Mine arrives monday. ......If it works great..... l'll post where I got it from  

[Chris O.]

17 minutes ago, GSP7 said:

O rileys gets crappy Cordone rebuilt ECMs, . and they are not programed to your Vin#

 

And I was told they dont have them for Cummins dodges anyway.. And I would not buy Cardone anyway

I bet they are not even ECMs but PCMs.

[trreed]

@JP907ATB i thought you told me that putting a 2.7k ohm resistor in the plug allowed the truck to idle normally.  Now the reading doesn't change?

[JP907ATB]

6 hours ago, trreed said:

@JP907ATB i thought you told me that putting a 2.7k ohm resistor in the plug allowed the truck to idle normally.  Now the reading doesn't change?

I put a 2.7k ohm resistor in IATplug and i can clear the po113 code and run truck, forcing IAT to read around 114. How ever something is forcing the truck into high idle and then what i believe to be 3 cyl high idle.