[connordunn]

I’ve got a 99 24v 5 speed. About a week ago was the last time I drove my truck and it was totally normally. Yesterday I got in and there was absolutely no throttle response from the moment it started. It just randomly quit. I’ve read that it’s probably the APPS but could also be the VP44 or even ecm. What diagnostic steps can I take to figure out what the problem is before I start spending money on parts that aren’t the solution? Thanks.

 

[1961 Cummins]

You need to scan it for codes to get started to know which direction to go.

 

[bigfish95971]

Yes scan for codes with a scan tool. Does it start and then die withing 5 seconds? Scan tools can be ahd for under 50 bucks at Harbor or Autozone and others.

 

[connordunn]

Yes scan for codes with a scan tool. Does it start and then die withing 5 seconds? Scan tools can be ahd for under 50 bucks at Harbor or Autozone and others.

Sorry I’m just getting back I didn’t get a notification that anyone responded to the thread. I am getting a PO122 and PO121. PO122 is throttle position sensor 1 circuit low and PO121 is throttle position sensor 1 performance. What do I do from here? I’ve put a new APPS on but I still have no throttle response.

 

[connordunn]

You need to scan it for codes to get started to know which direction to go.

Sorry I’m just getting back I didn’t get a notification that anyone responded to the thread. I am getting a PO122 and PO121. PO122 is throttle position sensor 1 circuit low and PO121 is throttle position sensor 1 performance. What do I do from here? I’ve put a new APPS on but I still have no throttle response.

 

[Drhillier]

Sounds like the throttle position sensor not the apps. You can confirm it with a volt meter or just buy one and install it.

 

[bigfish95971]

APPS and TPS are the same item, Llke Jim and James.

I need more information. Did it start and them die or did it sit and idle and not repose to the pedal movement? The codes so not mean necessarily the APPS(tps) is bad, but it means the voltage to or from is is off, It can be the apps or the voltage source from ECM and batteries harness etc.

So I need some more info and give you some things you can check.
You can start with cleaning all the battery terminals to a perfect shiny metal to metal connection. Another is pop the cover off the APPS bell crank assembly and make sure the throttle pedal cable and linkage under the cover are not broken. Check the wires and plug in bottom of the APPS for damage or corrosion.

if you are not getting notifications make sure the box is checked and your computer is not spamming them. Also fill out signature with everything about your truck.
A always get online almost every evening and all day when not working in afternoons. A am usually here until about 2am every night too.

If you do buy an apps at any point DO NOT buy a Timbo. Get any good brand, preferably a Wells (WVE), who make several store bands like Duralast at Autozone, Definitely not any 20 dollar no name brands.
Get back with those answers.

 

[connordunn]

APPS and TPS are the same item, Llke Jim and James.

I need more information. Did it start and them die or did it sit and idle and not repose to the pedal movement? The codes so not mean necessarily the APPS(tps) is bad, but it means the voltage to or from is is off, It can be the apps or the voltage source from ECM and batteries harness etc.

So I need some more info and give you some things you can check.
You can start with cleaning all the battery terminals to a perfect shiny metal to metal connection. Another is pop the cover off the APPS bell crank assembly and make sure the throttle pedal cable and linkage under the cover are not broken. Check the wires and plug in bottom of the APPS for damage or corrosion.

if you are not getting notifications make sure the box is checked and your computer is not spamming them. Also fill out signature with everything about your truck.
A always get online almost every evening and all day when not working in afternoons. A am usually here until about 2am every night too.

If you do buy an apps at any point DO NOT buy a Timbo. Get any good brand, preferably a Wells (WVE), who make several store bands like Duralast at Autozone, Definitely not any 20 dollar no name brands.
Get back with those answers.

So first I’ll start by saying I have already replaced the APPS with a Walker or Welker, I don’t remember exactly. It was the only manual off rock auto. I calibrated it too .60v at closed throttle and then like 3.60v at open throttle. And nothing works. The truck had no issues before and then I hopped in one day and had absolutely no throttle response. Truck still starts and runs. Seems to maybe be idling slightly higher but I’m not for sure what it’s normal idle is. I get normal voltage climb on the number 3 pin on the connector when moving the throttle but no response.

 

[bigfish95971]

OK. That is fine. PS the apps are all the same for manual or auto etc. I will guess Walker is ok. it is not your problem but you should resent the apps idle voltage by rotating it at .5v or what is written on the old one or ecm. >6 is a little high than it is supposed to be on most rucks. 3.6v at WOT is only a tiny bit low but ok. Usually they ae about 3.8v. Still not your problem.

Get out your ohm or continuity tester and check that wire form pin 3 to the ECM or VP44 or wherever it goes then any other wires between them that carry that voltage. You most likely have a break in that circuit which may include wires, ECM or VP etc.
Also pull codes with a scan tool.
Does you wait to start light come on immediately every time you turn the key to ON?
Is there any electrical mods on the truck at all?

 

[connordunn]

OK. That is fine. PS the apps are all the same for manual or auto etc. I will guess Walker is ok. it is not your problem but you should resent the apps idle voltage by rotating it at .5v or what is written on the old one or ecm. >6 is a little high than it is supposed to be on most rucks. 3.6v at WOT is only a tiny bit low but ok. Usually they ae about 3.8v. Still not your problem.

Get out your ohm or continuity tester and check that wire form pin 3 to the ECM or VP44 or wherever it goes then any other wires between them that carry that voltage. You most likely have a break in that circuit which may include wires, ECM or VP etc.
Also pull codes with a scan tool.
Does you wait to start light come on immediately every time you turn the key to ON?
Is there any electrical mods on the truck at all?

Ok I’ll check resistance in the wire. As stated earlier I’ve scanned it already and have codes PO122 and PO122. Wait to start light does take a couple seconds to come on normally and no there are no electrical mods on the truck.

 

[connordunn]

OK. That is fine. PS the apps are all the same for manual or auto etc. I will guess Walker is ok. it is not your problem but you should resent the apps idle voltage by rotating it at .5v or what is written on the old one or ecm. >6 is a little high than it is supposed to be on most rucks. 3.6v at WOT is only a tiny bit low but ok. Usually they ae about 3.8v. Still not your problem.

Get out your ohm or continuity tester and check that wire form pin 3 to the ECM or VP44 or wherever it goes then any other wires between them that carry that voltage. You most likely have a break in that circuit which may include wires, ECM or VP etc.
Also pull codes with a scan tool.
Does you wait to start light come on immediately every time you turn the key to ON?
Is there any electrical mods on the truck at all?

Also all 6 wires that go to the APPS go straight to the ecm.

 

[bigfish95971]

ECM should come on instantly for at least a second if warm(60F +) and not running grid heaters. The wire will be broken, corroded, or not. Also check all the harness plugs on APPS, ECM, and VP for any corossion on any of those tiny pins. Recheck for codes occasionally. With delayed WTS light, the ECM could very well be the issue. Delayed or no WTS light is usually indicative/definitive of a bad ECM. The light should come on immediately when the ECM boots up and powers the apps and all other circuits it runs. A delay is not booting up everything correctly or at all. Sometimes you will get a 602 or 606 or some other codes, but not always right away., sometimes not until it fails totally.

 

[connordunn]

ECM should come on instantly for at least a second if warm(60F +) and not running grid heaters. The wire will be broken, corroded, or not. Also check all the harness plugs on APPS, ECM, and VP for any corossion on any of those tiny pins. Recheck for codes occasionally. With delayed WTS light, the ECM could very well be the issue. Delayed or no WTS light is usually indicative/definitive of a bad ECM. The light should come on immediately when the ECM boots up and powers the apps and all other circuits it runs. A delay is not booting up everything correctly or at all. Sometimes you will get a 602 or 606 or some other codes, but not always right away., sometimes not until it fails totally.

I’m back with an update. I was wrong wait to start comes on immediately. I realized though that my vp44 isn’t kicking on. Yesterday it actually did kick on and the throttle worked. Now this morning I went out and it didn’t kick on and I don’t have any throttle response. Bad vp44?

 

[bigfish95971]

What do you mean"kicking on"? Does it idle but not accelerate or nor run or what. What is it doing and haw and when?