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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.

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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

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

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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.

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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.

IMG_0027.JPG

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

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Who are you going to get a Remanufactured ECM from ?

 

.

Edited by GSP7

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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.

 

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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 by JP907ATB

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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 by Chris O.

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

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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 by GSP7

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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 

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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   :cool:

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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.:)

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@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?

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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. 

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Then the ECM is good. If that resistor is clearing the codes. Then you back to the sensor being bad.

 

Dumb question, does the truck have a high idle kit on it? Is the switch left on high idle by chance?

Edited by Mopar1973Man

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11 hours ago, Chris O. said:

I bet they are not even ECMs but PCMs.:)

You are definitely correct. Almost all the big box stores list them as ECM's while they are actually PCM's.

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22 minutes ago, Mopar1973Man said:

Then the ECM is good. If that resistor is clearing the codes. Then you back to the sensor being bad.

 

Dumb question, does the truck have a high idle kit on it? Is the switch left on high idle by chance?

No such thing as a dumb question. Truck dose have high idle kit on it, the switch is off... it’s the actuator type. Flip switch and tap foot feed because actuator isn’t strong enough to open throttle by itself. I can engage and disengage high idle just fine. While high idle is engaged truck runs/sounds good at 1200 rpm. This kit dose not give me 3 cyl option. If i ever get this beast figured out i think I’m going to order one of the moparman kits. Of the resistor con IAT plug allows me to clear code, but truck is still doing high idle and 3cyl high idle by itself in 40 degree weather. I’ve put two new IAT sensors in already, i suppose i could get two bad ones in a row from oreillys.. I’m going to have a look at the oil pressure sensor and the cps this morning I’m hoping i find a problem with one of those.

Dose edge juice w/ additude mess with IAT, cts readings? I know there’s a map fooler.. i have the edge main harness disconnected and the map fooler unplugged.. so edge shouldn’t be doing anything now 

Edited by JP907ATB

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I need to know what values your live data tools shows for both ECT and IAT on a cold engine. Thet should match exactly. Both ECT and IAT are the same thermistor and typically are exactly the same on a cold start. +/- 1*F is nothing to worry about but if it greatly different then I would have to say the sensor is bad.  

 

6 cylinder high idle requires <32*F IAT with gird heater firing. 3 cylinder high idle required <15*F with gird heaters firing. This is why I need to see the IAT and ECT values at first key on. This will validate the sensor and it value. 

 

Another dumb question. The sensor is it stock location at the rear of the head correct? I've seen some people move then to the intake horn this will create all kind of weird problems because the IAT temp table is based on it location so if it has be relocated then it will make things behave wierd. 

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Yes the sensor is still in the original location on the back of head, drivers side. Right now the truck has the starter out and ecm plug out, after i test the wiring to the other two sensors i will put it back together and look at live data and get back to you. But normally the ECT read outside temp +\- a few degrees but IAT always reads -40, it read -40 as soon as i put new sensor in.. could something in my wiring or computer be shorting out the sensor? 

So it’s not cold enough here now for truck to be going into highidle or 3cyl high idle by itself 

The other weird thing is if i plug in my edge monitor and bring up IAT and CTS on there they almost match identical

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