First time posting, I've used your advice on many previous issues reading different forums and such. Hopefully you can shoot a clear answer for me here cause I'm stuck.

1999 Dodge Cummins, I've had periodic dead pedal for the last 2 years. Would drop to an idle at highway speed and no throttle response. Shut truck off, turn back on, problem went away. 

Now the truck is stuck at a slightly high idle at 1,100 RPM. No Throttle response at all. I just replaced APPS with Napa replacement. No different.

-Vp44 replaced 3 years ago

 

Some other history:

-one day no gauges worked and got (No Bus) on odometer. Next day "problem fixed itself"

-A month ago the Wait to Start light would not come on before start up. But once running voltage would draw like grid heater was working while running. A week later "problem fixed itself". Wait to Start works fine.

So after this extremely long post (sorry) are these symptoms of a faulty ECM?? 

 

It acts like a failed ECM. 

 

I need you to check for error codes using an OBDII tool and list all the error codes numbers you get. 

2 minutes ago, Mopar1973Man said:

It acts like a failed ECM. 

 

I need you to check for error codes using an OBDII tool and list all the error codes numbers you get. 

Yes please check for codes I'm also curious if a timbo apps would be a better choice compared to a napa apps. Mike do you know anything about napas? If there units are junk that could easily be an issue still. 

1 minute ago, Marcus2000monster said:

Mike do you know anything about napas?

 

Most likely a direct replacement with logic chips to control the validation switches by voltage. Timbo's is the only APPS without electronics completely and is completely mechanical. No voltage to set and all based on bellcrank angle not voltage. 

1 minute ago, Mopar1973Man said:

 

Most likely a direct replacement with logic chips to control the validation switches by voltage. Timbo's is the only APPS without electronics completely and is completely mechanical. No voltage to set and all based on bellcrank angle not voltage. 

Hmm I would almost try a Timbo before buying a new ecm if I were him. But I would also do ECM failure testing before the apps...

Just unplug the APPS sensor. If the idle doesn't return to normal it's NOT the APPS sensor. 

1 minute ago, Mopar1973Man said:

Just unplug the APPS sensor. If the idle doesn't return to normal it's NOT the APPS sensor. 

@DooLittleDiesel I would try doing this! Mike I don't see an article about ecm failure clue us in please.

1 minute ago, Marcus2000monster said:

@DooLittleDiesel I would try doing this! Mike I don't see an article about ecm failure clue us in please.

There is a good reason for this. The ECM is a mysterious beast. There are several proven symptoms that point to the ECM. Mine failed back in 09 with none of the symptoms most people have. Nobody knew much o  how to help then and with a $2500 price tag back then it was a tough sell to see the dealer back then. I for one am gun shy of making that call with some one else's money. I am sure @Mopar1973Man might some thing to add to that.

Thanks for the quick replies

Here are the codes

P0121

P0122

P1693

These codes led me to believe it was the Apps. But that didn't fix it.

That's the problem with ECM failure there is a lot of different ways they fail. 

 

• P0606 error code
• All sensors have either hi or lo volt error codes
• Wait To Start light not coming on or delay extremely long.
• Soon as it starts goes to WOT regardless of throttle position. 
• Doesn't start at all.
• Limited pedal where the ECM will throttle to like 30 MPH but no higher. 

Like I said there is a lot of fails for the ECM but I like to play by a 2 smoking gun rule. In other words I'm looking for 2 different test to fail the ECM so like the ECM producing the P0606 and the WTS light is lagging. That would be a for sure fail of the ECM.

 

Now @DooLittleDiesel might have a bad VP44 too that in not playing nice too but hard to make that call with little information.

1 minute ago, DooLittleDiesel said:

Thanks for the quick replies

Here are the codes

P0121

P0122

P1693

These codes led me to believe it was the Apps. But that didn't fix it.

 

 

 

I unplugged APPS and started the truck. The truck idled normal speed approximately 850 RPMs.

What does this mean?

4 minutes ago, DooLittleDiesel said:

I unplugged APPS and started the truck. The truck idled normal speed approximately 850 RPMs.

What does this mean?

Mike correct if wrong but I believe that that's your issue unless I'm thinkin backward. If so go to the store section of this forum and get you the Timbo apps. 

Good The ECM is most likely fine. The APPS sensor is most likely set up wrong or bad out of the box. Need to measure the voltage on the Light Blue/Black wire and see what the idle position voltage is. It should be around 0.4 to 0.5 volts typically. If it's too high then the APPS will trip the validation switch causing the high idle near 1,100 RPM's.

Just now, Mopar1973Man said:

Good The ECM is most likely fine. The APPS sensor is most likely set up wrong or bad out of the box. Need to measure the voltage on the Light Blue/Black wire and see what the idle position voltage is. It should be around 0.4 to 0.5 volts typically. If it's too high then the APPS will trip the validation switch causing the high idle near 1,100 RPM's.

I bet he is happy to hear this lol! 

Just now, Marcus2000monster said:

Mike correct if wrong but I believe that that's your issue unless I'm thinkin backward.

 

Just unplugging the APPS will force the ECM to control the idle for the VP44. 

 

1 minute ago, Marcus2000monster said:

If so go to the store section of this forum and get you the Timbo apps. 

 

Why spend someone money if they don't need the part? 

2 minutes ago, Mopar1973Man said:

 

Just unplugging the APPS will force the ECM to control the idle for the VP44. 

 

 

Why spend someone money if they don't need the part? 

So he goes broke lol! Just kidding. Yes he should definatly test apps voltage first.

So I plugged the sensor back in and started the truck to see if it would idle at 1,100 RPM again. It idled at 850 and I Have Throttle Response again!!?? Like the truck is back to normal. What is this things deal!

Ok then do me another thing. Do a APPS reset.

 

I did have the batteries unplugged for 20 minutes.. Would that reset anything?

No not really. You need to do it again and then proceed to do the throttle movement to program the ECM the limits of the APPS sensor. 

 

Disconnecting the batteries does not reset anything else including error codes. The ECM can hold information for over 10 years and still retain the error codes without power/batteries for that long. 

7 minutes ago, DooLittleDiesel said:

So I plugged the sensor back in and started the truck to see if it would idle at 1,100 RPM again. It idled at 850 and I Have Throttle Response again!!?? Like the truck is back to normal. What is this things deal!

It is the Dodge in your Cummins. It is like a woman, mysterious at times.