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thanks. Checking the wires at the tp pigtail.
With key on engine off, I read 5.03 volts on pin E and H, and 4.93v on pin F and G. Is that you guys are getting ?
thanks. Checking the wires at the tp pigtail.
With key on engine off, I read 5.03 volts on pin E and H, and 4.93v on pin F and G. Is that you guys are getting ?
thanks. Checking the wires at the tp pigtail.
With key on engine off, I read 5.03 volts on pin E and H, and 4.93v on pin F and G. Is that you guys are getting ?
So there's a possible problem right there. 5v Reference is normal, that's 5v from the PCM, Pin F & G is the return to the PCM, as in that's the TPS position to the PCM. It's a resistance circuit so voltage in and the resistance varies as the blade moves. Schematic would 100% verify this, I'm gathering that from the connector diagram there and from what I've seen over the years.
If you measured with that unplugged and got those results, there's your short as the code says. Have to chase that wiring from the TB Connector to the PCM and find it.
Long time ago I bolted a Transmission to an Engine and pinched all the wires in the Bell Housing. Had all kinds of odd codes so went investigating and found that. **** happens we've all done it.
So there's a possible problem right there. 5v Reference is normal, that's 5v from the PCM, Pin F & G is the return to the PCM, as in that's the TPS position to the PCM. It's a resistance circuit so voltage in and the resistance varies as the blade moves. Schematic would 100% verify this, I'm gathering that from the connector diagram there and from what I've seen over the years.
If you measured with that unplugged and got those results, there's your short as the code says. Have to chase that wiring from the TB Connector to the PCM and find it.
Long time ago I bolted a Transmission to an Engine and pinched all the wires in the Bell Housing. Had all kinds of odd codes so went investigating and found that. **** happens we've all done it.
Thanks. I found this schematic for TAC on 04. Do I trace wires F and G back to the TAC or PCM? Do we know F and G should read with key on engine off?
Looks like both of them go to the TAC Module in this case so trace all 8 of them wires from the Throttle Body to the TAC Module. Key on Engine off it should have a much less voltage than 5v because the Throttle Body is barely open.
good morning,
Shouldn't pin F and G have a range between 0,5-4,5V (Signal), under 0,5V and over 4,5 indicate something is wrong.
Thinking out loud here
good morning,
Shouldn't pin F and G have a range between 0,5-4,5V (Signal), under 0,5V and over 4,5 indicate something is wrong.
Thinking out loud here
/C
yes, my guess is that B and D (low reference ) are missing so F and G would output close to the 5v reference.
did you get a chance to get a reading at F and G from yours, key on, engine off?
3.55 and 1.49 on the other one at 23.2 percent throttle.
key on engine off
Did you unplug the TPS sensor at the throttle body and read 3.55 volts, and 1.49v on F and G with key on engine off ?? What do you mean by 23.2% throttle? how to get throttle % when the pigtail is unplugged? Not sure if i understand this correctly.
Thanks
Did you unplug the TPS sensor at the throttle body and read 3.55 volts, and 1.49v on F and G with key on engine off ?? What do you mean by 23.2% throttle? how to get throttle % when the pigtail is unplugged? Not sure if i understand this correctly.
Thanks
Sorry...
Plug was connected to get some proper results.
If not connected i think the signal wires will be "floating"
Sorry...
Plug was connected to get some proper results.
If not connected i think the signal wires will be "floating"
OK, thanks.
Just curious, looking at your Post# 20. Your throttle position is at 7.1%, but I see your Long term fuel trims at -25%, and 21.0% on Bank 1 and 2, that would make the throttle % higher as the rpm is up. Do you have any lean or reach condition?
It is running crazy rich as i haven't done anything about that yet, that is "next step"
When i took this screen dump i think i just reset the long terms thats why it looks strange
With key on and engine of the blade is a bit more open than when running, not sure but look at it as a "crank" mode, when engine starts it will close.
It is running crazy rich as i haven't done anything about that yet, that is "next step"
When i took this screen dump i think i just reset the long terms thats why it looks strange
With key on and engine of the blade is a bit more open than when running, not sure but look at it as a "crank" mode, when engine starts it will close.
Ok, makes sense why you tps % is high. Yes the blade always stays open with the DBW throttle, so the engine can start up, once its running, it will close or open according to the pedal position.
With reach, and lean conditions, testing the TPS readings wont give you the correct information as those conditions cause the throttle to open more thn it would
So there's a possible problem right there. 5v Reference is normal, that's 5v from the PCM, Pin F & G is the return to the PCM, as in that's the TPS position to the PCM. It's a resistance circuit so voltage in and the resistance varies as the blade moves. Schematic would 100% verify this, I'm gathering that from the connector diagram there and from what I've seen over the years.
If you measured with that unplugged and got those results, there's your short as the code says. Have to chase that wiring from the TB Connector to the PCM and find it.
Long time ago I bolted a Transmission to an Engine and pinched all the wires in the Bell Housing. Had all kinds of odd codes so went investigating and found that. **** happens we've all done it.
I looked more into this, and I believe that the reading value are okay when reasuring at the TPS pigtail unplug. F, and G are reading 4.93v because they are pulling that from the 5v Reference wire H, and E. When measuring F, and G with the TPS plugged in, the reading fluactuate between 0.5v and 4v as the throttle opens. The low reference stay at 0.5v. So again, reading F, and G with key on engine off, pigtail unplug would definitely ready close to the 5v from the 5v Reference wires.
I looked more into this, and I believe that the reading value are okay when reasuring at the TPS pigtail unplug. F, and G are reading 4.93v because they are pulling that from the 5v Reference wire H, and E.
Tell me how, when something is unplugged, where 4 wires that are completely separate will "pull" voltage from each other?
I really want to know. This isn't enough voltage or amperage for magnetic inductance so there's that.
I have two Degrees in Electronics and do that for my job, but clearly you're an expert above us here. I don't even know why the **** any us are commenting on this at this point. You have this figured out it seems.
So why isn't it fixed and running right yet?
Last edited by the_merv; Jan 28, 2025 at 05:33 PM.
I already told you what to do. Keep in mind you're the one with the vehicle problem, the codes literally tell you it. Two completely separate circuits shorted together. Anyone who knows electronics would see that and start looking at the wiring. I said that a few times. You just won't listen so we are wasting our time.
This is comical at this point tho, you're over there "I think this is normal because it's unplugged and the magical electric pixies are jumping from each unconnected wire.."
This is why in nature some animals eat their young. I'm out at this point the rest of you can handle this mess...
Last edited by the_merv; Jan 28, 2025 at 06:21 PM.
Tell me how, when something is unplugged, where 4 wires that are completely separate will "pull" voltage from each other?
I really want to know. This isn't enough voltage or amperage for magnetic inductance so there's that.
I have two Degrees in Electronics and do that for my job, but clearly you're an expert above us here. I don't even know why the **** any us are commenting on this at this point. You have this figured out it seems.
So why isn't it fixed and running right yet?
Originally Posted by the_merv
Go look up what it means when wires are shorted.
I already told you what to do. Keep in mind you're the one with the vehicle problem, the codes literally tell you it. Two completely separate circuits shorted together. Anyone who knows electronics would see that and start looking at the wiring. I said that a few times. You just won't listen so we are wasting our time.
This is comical at this point tho, you're over there "I think this is normal because it's unplugged and the magical electric pixies are jumping from each unconnected wire.."
This is why in nature some animals eat their young. I'm out at this point the rest of you can handle this mess...
Sorry I didnt mean to insult anyone here, nor I thing that I am in expert in any of this. I am just a DIY guy looking for help and answers.
I am not an electrician, and do not have much knowledge about the subject, but I believe that I do understand a little bit of it. Now TP 1 and TP 2 are Potentiometer sensors. Read this below from GM DTC P2135 description:
----------------------------------------------------------------------------------------------------------------------------------------------------
The throttle position (TP) sensors 1 and 2 are potentiometer type sensors, each with the following three
circuits:
• A 5-volt reference circuit
• A low reference circuit
• A signal circuit
The TP sensors are used to determine the throttle plate angle for various engine management systems. The
control module provides each TP sensor a 5-volt reference circuit and a low reference circuit. The TP sensors
then provide the control module with signal voltage proportional to throttle plate movement. Both TP sensor
signal voltages are low at closed throttle and increase as the throttle opens. When the control module detects
that TP sensor 1 signal and the TP sensor 2 signals disagree, or signal voltages are outside the predetermined
range, this DTC sets.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Again with my limited knowledge on this, I came up with my conclusion based by looking at the TPS and TAC circuit diagram i had posted in previous post, and this Potentiometer drawing below. Maybe with your expertise on the subject you will explain to us. Thanks for your input.
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