• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Throttle position sensor - Voltage on output wire

Set the timing today -- it was off by just a few degrees according to the toothpick holes

It starts easier now and runs better cold but no change when it warms up -- idle still drops and it coughs and spits

Get it up to 1500 plus rpm and it doesn't sound bad but let it drop to idle from there and it barely runs

I've got a friend with a real scanner -- wants to see it -- maybe his scanner will tell me something -- just have to trailer it to his shop
 
Are you going to do a compression check or not ??????


I have to although I've been avoiding it -- Been hoping to stumble across the problem and not have to pull the head

If I do find I need to pull the head I'll be looking for a replacement TUPY head

I'm not going to put much work into a head thats prone to cracking
 
I have to although I've been avoiding it -- Been hoping to stumble across the problem and not have to pull the head

If I do find I need to pull the head I'll be looking for a replacement TUPY head

I'm not going to put much work into a head thats prone to cracking



Ok,You can lead a horse to water but,you can't make him drink.
 
So I kind of scanned through and didn't see that anyone answered your original question.
Yes, there is supposed to be 5v on the signal wire when unplugged. It's a carrier voltage.

The three pins on the TPS harness should test as follows, KOEO, sensor unplugged:
Pin 1: sensor ground, 0v
Pin 2: sensor signal, 5v
Pin 3: 5v supply, 5v

All 3 wire Chrysler sensors test out this way, though pin order may be different per sensor.
 
So I kind of scanned through and didn't see that anyone answered your original question.
Yes, there is supposed to be 5v on the signal wire when unplugged. It's a carrier voltage.

The three pins on the TPS harness should test as follows, KOEO, sensor unplugged:
Pin 1: sensor ground, 0v
Pin 2: sensor signal, 5v
Pin 3: 5v supply, 5v

All 3 wire Chrysler sensors test out this way, though pin order may be different per sensor.


I've searched many forums in the past month -- this is the 1st time I have seen this answered this way

Most threads just go unanswered -- In fact all the threads I've seen have gone unanswered

I kinda just gave up looking for the source of the voltage on the sensor wire

I still get P0122 sometimes -- tried 3 TPS and all the same -- wasn't going to worry about it till I found the source of my troubles


Compression check this week -- Gotta see if I can source a decent compression check gauge -- I have one but I think it's for small engines -- has a rubber expanding plug for the spark plug end -- I've never used it -- Came with a bunch of tool I bought out of a barn
 
FYI, here's a TPS test procedures chart. I use a safety pin as a back probe.

TPS%20TESTS%20final.jpg

.
 
Finally did a compression test today -- I was able to borrow a snap on compression test kit from a friend -- made it super easy

Cylinder# --------- PSI
1 ---------- 175
2 ---------- 0
3 ---------- 130
4 ---------- 162
5 ---------- 180
6 ---------- 178

I'll pull the valve cover tomorrow and see what is going on -- I have the stuff to do a leak down test if it isn't obvious
 
Pulled the valve cover off and found the pushrod for cylinder 2 exhaust valve disconnected from the rocker arm -- It was just laying there in the hole -- Bent like "S"

The exhaust valve is stuck open, spring is compressed as much as it can -- rocker is just loose on top

guess this thread about throttle position sensor issues is over...
 
Hi...i am a new user here. In my case TPS signal wire always has a little bit of voltage on it, even with it unplugged, but nothing like 4 volts, more like 1/2 a volt or so. No idea why it's like that, but it doesn't throw any codes, so I suspect it's an OEM design feature of some sort.
 
Sorry to resolve an old thread. If there's any chance you are still active - did you find a solution to the problem? I have the same symptoms. Cleaned the grounds and still getting around 4.6 volts on pin A23 at the PCM. Let me know if you found anything!
 
Back
Top